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/am3517_evm.h b/include/configs/am3517_evm.h
index 5c61697..6500878 100644
--- a/include/configs/am3517_evm.h
+++ b/include/configs/am3517_evm.h
@@ -19,6 +19,7 @@
 #define CONFIG_OMAP		1	/* in a TI OMAP core */
 #define CONFIG_OMAP34XX		1	/* which is a 34XX */
 #define CONFIG_OMAP3_AM3517EVM	1	/* working with AM3517EVM */
+#define CONFIG_OMAP_COMMON
 
 #define CONFIG_EMIF4	/* The chip has EMIF4 controller */