arm64: allwinner: a64: add proper support for the Wi-Fi on BPi M64

BPi M64 has an AP6212 Wi-Fi/Bluetooth combo module, and the Wi-Fi SDIO
card is connected to the mmc1 controller.

The pwrseq of the mmc1 (used to reset the card) used to missing, and the
out-of-band interrupt line of the card is not specified.

Fix these issues for proper Wi-Fi support of BPi M64.

Signed-off-by: Icenowy Zheng <icenowy@aosc.io>
Signed-off-by: Chen-Yu Tsai <wens@csie.org>