mmc: Kconfig: Add Arasan SDHCI entry

Add Arasan SDHCI entry to Kconfig and fix all references.

Signed-off-by: Michal Simek <michal.simek@xilinx.com>
diff --git a/include/configs/zynq_zc770.h b/include/configs/zynq_zc770.h
index f49715b..6121c09 100644
--- a/include/configs/zynq_zc770.h
+++ b/include/configs/zynq_zc770.h
@@ -14,10 +14,7 @@
 
 #define CONFIG_SYS_NO_FLASH
 
-#if defined(CONFIG_ZC770_XM010)
-# define CONFIG_ZYNQ_SDHCI0
-
-#elif defined(CONFIG_ZC770_XM012)
+#if defined(CONFIG_ZC770_XM012)
 # undef CONFIG_SYS_NO_FLASH
 
 #endif