riscv: sophgo: dts: add mmc controllers for SG2042 SoC

SG2042 has two MMC controller, one for emmc, another for sd-card.

Signed-off-by: Chen Wang <unicorn_wang@outlook.com>
Link: https://lore.kernel.org/r/03ac9ec9c23bbe4c3b30271e76537bdbe5638665.1722847198.git.unicorn_wang@outlook.com


Signed-off-by: Inochi Amaoto <inochiama@outlook.com>