chore(zone): reduce linux config

[alexandermerritt]

Our current fragment is quite small.

What that means: default-enabled config options in Kconfig that are not explicitly disabled in our fragment, will be enabled once merged with a defconfig for the architecture. Examples include wireless hardware support and networking, bluetooth, sound, etc. which we all do not need for zone kernels.

Goals: reduce the amount of text in the kernel, second to reduce build times.

This is one of many in the future to come; we'll need to is not set any default-enabled configuration options we do not want. For future kernels, we'll need to check for any newly introduce configuration options that are default-enabled and repeat for them.

I'd like to properly generate the fragment rather than have us go with manually editing the config when we want to tweak something.

[alexandermerritt]

Kernel finished building for me on a 32-core EPYC machine with no caching:

________________________________________________________
Executed in  376.62 secs    fish           external
   usr time  101.27 mins  654.00 micros  101.27 mins
   sys time   15.08 mins  489.00 micros   15.08 mins

[alexandermerritt]

I want to try this kernel out with the e2e tests somehow before we merge in.

[alexandermerritt]

Still lots of time spent on net drivers. I captured the build output to a log file. This is the count of directories associated with a C file that is built:

~> rg CC build.log | rg drivers/net | awk '{print $NF}' | xargs dirname | sort | uniq -c | sort | tail -40
      9 drivers/net/ethernet/wangxun/libwx
     10 drivers/net/can/sja1000
     10 drivers/net/ethernet/netronome/nfp/flower
     11 drivers/net/arcnet
     11 drivers/net/ethernet/google/gve
     11 drivers/net/ethernet/intel/e1000e
     11 drivers/net/ethernet/intel/igb
     11 drivers/net/ethernet/mellanox/mlx5/core/esw
     11 drivers/net/ethernet/mscc
     12 drivers/net/can/spi/mcp251xfd
     12 drivers/net/ethernet/intel/fm10k
     12 drivers/net/ethernet/intel/idpf
     13 drivers/net/ethernet/intel/igc
     13 drivers/net/ethernet/pensando/ionic
     13 drivers/net/netdevsim
     13 drivers/net/ovpn
     14 drivers/net/ethernet/qlogic/qlcnic
     14 drivers/net/ethernet/sfc/falcon
     14 drivers/net/wireguard
     15 drivers/net/ethernet/marvell/prestera
     15 drivers/net/ethernet/mellanox/mlx5/core/en_accel
     16 drivers/net/ethernet/intel/i40e
     17 drivers/net/ethernet/meta/fbnic
     18 drivers/net/ethernet/huawei/hinic
     18 drivers/net/ethernet/mellanox/mlx5/core/steering/hws
     19 drivers/net/ethernet/mellanox/mlx5/core/en/tc/act
     20 drivers/net/ethernet/huawei/hinic3
     20 drivers/net/ethernet/mellanox/mlx5/core/steering/sws
     20 drivers/net/ethernet/netronome/nfp
     20 drivers/net/ethernet/sfc/siena
     22 drivers/net/ethernet/mellanox/mlx5/core/lib
     23 drivers/net/ethernet/intel/ixgbe
     27 drivers/net/ethernet/qlogic/qed
     30 drivers/net/ethernet/mellanox/mlx5/core/en
     32 drivers/net/ethernet/mellanox/mlx4
     33 drivers/net/ethernet/stmicro/stmmac
     39 drivers/net/ethernet/sfc
     49 drivers/net/ethernet/intel/ice
     49 drivers/net/ethernet/mellanox/mlxsw
     54 drivers/net/ethernet/mellanox/mlx5/core

and overall

~> rg CC build.log | awk '{print $NF}' | xargs dirname | sort | uniq -c | sort | tail -40
     30 drivers/net/ethernet/mellanox/mlx5/core/en
     31 fs/ubifs
     31 net/netfilter/ipvs
     32 drivers/net/ethernet/mellanox/mlx4
     33 drivers/net/ethernet/stmicro/stmmac
     34 drivers/iio/pressure
     35 drivers/gpu/drm/amd/amdgpu/../pm/powerplay/hwmgr
     36 drivers/staging/fbtft
     37 fs/afs
     39 drivers/gpu/drm/amd/amdgpu/../amdkfd
     39 drivers/net/ethernet/sfc
     43 fs/smb/client
     44 drivers/infiniband/hw/hfi1
     46 drivers/md
     49 drivers/iio/dac
     49 drivers/net/ethernet/intel/ice
     49 drivers/net/ethernet/mellanox/mlxsw
     54 drivers/net/ethernet/mellanox/mlx5/core
     58 drivers/infiniband/core
     59 drivers/iio/accel
     61 drivers/crypto/intel/qat/qat_common
     63 drivers/hwmon/pmbus
     63 drivers/iio/light
     63 fs/btrfs
     86 drivers/hwmon
     89 drivers/hid
     96 drivers/iio/adc
    122 drivers/comedi/drivers
    233 drivers/gpu/drm/amd/amdgpu

[alexandermerritt]

Shouldn't all the GPU options live in a fragment we have, not the base zone configuration file?