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/omap3_overo.h b/include/configs/omap3_overo.h
index 3e018c0..88380a4 100644
--- a/include/configs/omap3_overo.h
+++ b/include/configs/omap3_overo.h
@@ -14,6 +14,7 @@
 #define CONFIG_OMAP34XX				/* which is a 34XX */
 #define CONFIG_OMAP3_OVERO			/* working with overo */
 #define CONFIG_OMAP_GPIO
+#define CONFIG_OMAP_COMMON
 
 #define CONFIG_SDRC				/* The chip has SDRC controller */