mmc: sdhci-esdhc-imx: add alternate ARCH_S32 dependency to Kconfig
MMC_SDHCI_ESDHC_IMX requires ARCH_MXC despite also being used on
ARCH_S32, which results in unmet dependencies when compiling strictly
for ARCH_S32. Resolve this by adding ARCH_S32 as an alternative to
ARCH_MXC in the driver's dependencies.