Convert CONFIG_HSMMC2_8BIT to Kconfig

This converts the following to Kconfig:
   CONFIG_HSMMC2_8BIT

Signed-off-by: Tom Rini <trini@konsulko.com>
diff --git a/drivers/mmc/Kconfig b/drivers/mmc/Kconfig
index bf4d994..698c91c 100644
--- a/drivers/mmc/Kconfig
+++ b/drivers/mmc/Kconfig
@@ -385,6 +385,11 @@
 
 	  If unsure, say N.
 
+config HSMMC2_8BIT
+	bool "Enable 8-bit interface for eMMC (interface #2)"
+	depends on MMC_OMAP_HS && (OMAP44XX || OMAP54XX || DRA7XX || AM33XX || \
+		AM43XX || ARCH_KEYSTONE)
+
 config SH_SDHI
 	bool "SuperH/Renesas ARM SoCs on-chip SDHI host controller support"
 	depends on ARCH_RMOBILE