dt-bindings: mmc: sunxi: add compatible strings for Allwinner A523

The Allwinner A523 uses the same MMC IP as the D1.

Introduce the new specific compatible strings, and use them with
fallbacks to the D1 strings.

Signed-off-by: Andre Przywara <andre.przywara@arm.com>
Acked-by: Conor Dooley <conor.dooley@microchip.com>
Link: https://lore.kernel.org/r/20250307005712.16828-3-andre.przywara@arm.com


Signed-off-by: Ulf Hansson <ulf.hansson@linaro.org>