In the previous version, the sdhci alias was set to mmc1: an artifact
leftover from the port from vendor kernel. Update the alias to mmc0 to
match the device's boot order.

Fixes: 6fb2d1549786 ("arm64: dts: rockchip: Add rock-5b board")
Signed-off-by: Christopher Obbard <chris.obbard@collabora.com>
Link: https://lore.kernel.org/r/20230110195352.272360-4-chris.obbard@collabora.comSigned-off-by: Heiko Stuebner <heiko@sntech.de>