arm64: allwinner: a100: Add MMC related nodes

The A100 has 3 MMC controllers, one of them being especially targeted to
eMMC. Let's add nodes on dts.

Signed-off-by: Yangtao Li <frank@allwinnertech.com>
Reviewed-by: Andre Przywara <andre.przywara@arm.com>
Signed-off-by: Cody Eksal <masterr3c0rd@epochal.quest>
Link: https://patch.msgid.link/20241031070232.1793078-10-masterr3c0rd@epochal.quest


Signed-off-by: Chen-Yu Tsai <wens@csie.org>