ARM: OMAP: Add CONFIG_OMAP_COMMON

Adding a new CONFIG_OMAP_COMMON which is included by all boards
that needs to build cpu/armv7/omap-common folder.

Signed-off-by: Lokesh Vutla <lokeshvutla@ti.com>
diff --git a/include/configs/mcx.h b/include/configs/mcx.h
index c2b1631..85ae016 100644
--- a/include/configs/mcx.h
+++ b/include/configs/mcx.h
@@ -16,6 +16,7 @@
 #define CONFIG_OMAP34XX			/* which is a 34XX */
 #define CONFIG_OMAP3_MCX		/* working with mcx */
 #define CONFIG_OMAP_GPIO
+#define CONFIG_OMAP_COMMON
 
 #define MACH_TYPE_MCX			3656
 #define CONFIG_MACH_TYPE	MACH_TYPE_MCX