mmc: atmel: rename CONFIG_ATMEL_SDHCI to CONFIG_MMC_SDHCI_ATMEL

Make the naming scheme consistent; all SDHCI-base drivers prefixed
with CONFIG_MMC_SDHCI_.

While we are here, add "depends on ARCH_AT91".

Signed-off-by: Masahiro Yamada <yamada.masahiro@socionext.com>
diff --git a/drivers/mmc/Makefile b/drivers/mmc/Makefile
index e63f439..e78bd0d 100644
--- a/drivers/mmc/Makefile
+++ b/drivers/mmc/Makefile
@@ -14,7 +14,6 @@
 endif
 
 obj-$(CONFIG_ARM_PL180_MMCI) += arm_pl180_mmci.o
-obj-$(CONFIG_ATMEL_SDHCI) += atmel_sdhci.o
 obj-$(CONFIG_BFIN_SDH) += bfin_sdh.o
 obj-$(CONFIG_MMC_DAVINCI)		+= davinci_mmc.o
 
@@ -53,6 +52,7 @@
 
 # SDHCI
 obj-$(CONFIG_MMC_SDHCI)			+= sdhci.o
+obj-$(CONFIG_MMC_SDHCI_ATMEL)		+= atmel_sdhci.o
 obj-$(CONFIG_MMC_SDHCI_BCM2835)		+= bcm2835_sdhci.o
 obj-$(CONFIG_MMC_SDHCI_CADENCE)		+= sdhci-cadence.o
 obj-$(CONFIG_MMC_SDHCI_KONA)		+= kona_sdhci.o