[MMC] Prevent au1xmmc.c breakage on non-Au1200 Alchemy

The driver is selectable on other than Au1200 Alchemy systems but won't
build nor work - there is no MMC hw.
Signed-off-by: Ralf Baechle <ralf@linux-mips.org>
Signed-off-by: Russell King <rmk+kernel@arm.linux.org.uk>

drivers/mmc/Kconfig

@@ -84,7 +84,7 @@ config MMC_WBSD
 
 config MMC_AU1X
 	tristate "Alchemy AU1XX0 MMC Card Interface support"
-	depends on SOC_AU1X00 && MMC
+	depends on MMC && SOC_AU1200
 	help
 	  This selects the AMD Alchemy(R) Multimedia card interface.
 	  If you have a Alchemy platform with a MMC slot, say Y or M here.