Orange Pi Zero 2 (Allwinner H616): BSP bring-up + uwe5622 SDIO WiFi driver - #84

Summary

Adds NetBSD support for the Orange Pi Zero 2 (Allwinner H616), including:

• H616 SoC bring-up: new CCU (clock controller) and GPIO drivers (sun50i_h616_ccu.c/h, sun50i_h616_gpio.c), plus real IRQ/DMA support added to sunxi_mmc.c for the SD/MMC controllers.
• uwe5622_sdio(4): a new driver for the UNISOC (Spreadtrum) uwe5622 SDIO Wi-Fi chip found on this board. Firmware does the full 802.11 MAC internally; the driver implements the SDIO transport, the vendor SPRDWL command/event protocol, and the net80211/wpa_supplicant(8) bridge. Supports open networks and WPA2-Personal (PSK/CCMP) on both 2.4GHz and 5GHz. WPA3/SAE is not supported - the firmware's own command ABI has no AKM/auth-type value for it.
• A small addition to the generic LED framework (led_set_by_name()) used to drive a TX/RX activity LED from the driver.
• A man page, uwe5622_sdio(4).

The driver is split into several files under sys/dev/sdmmc/ (if_uwe5622_sdio.c plus _transport.c/_fw.c/_proto.c/_data.c/_net80211.c and a shared if_uwe5622_sdiovar.h), following the same pattern as sdmmc.c/sdmmc_io.c/sdmmc_mem.c in the same directory. Firmware/calibration blobs live under sys/dev/microcode/uwe5622/, matching the existing convention used by bge/tigon/atmel.

Test plan

All tested on real Orange Pi Zero 2 hardware, netbooted:

• Open (unencrypted) network association, DHCP, sustained TCP/UDP throughput (iperf3), ping
• WPA2-PSK/CCMP association via wpa_supplicant, full 4-way handshake, pairwise + group key install
• 2.4GHz and 5GHz operation against both dedicated test APs and a real production mesh router, including a live roam between mesh nodes
• Sustained throughput ~35-80 Mbit/s depending on band, near-zero idle CPU via real SDIO hardware interrupts (vs. polling)
• TX/RX activity LED confirmed working during sustained traffic
• Full regression pass after splitting the driver into multiple files identical behavior to the pre-split single-file version

Known limitations

• WPA3-Personal (SAE) is not supported (firmware command ABI limitation)
• The Bluetooth function of the same physical chip is not yet implemented

This work is dedicated to my son, who's about to turn one, and to my lovely wife ❤️