mmc: sdhci-of-aspeed: Add dependency on ARCH_ASPEED

The MMC_SDHCI_OF_ASPEED is part of the Aspeed silicon so it makes
sense to depend on ARCH_ASPEED and for compile testing.

Signed-off-by: Peter Robinson <pbrobinson@gmail.com>
Link: https://lore.kernel.org/r/20220916115602.370003-1-pbrobinson@gmail.com


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