OMAP: include sys_proto.h from boot-common

Include asm/arch/sys_proto.h for gpmc_init prototype.
Without this we get a warning while building for AM335x.

Signed-off-by: Ilya Yanok <ilya.yanok@cogentembedded.com>

arch/arm/cpu/armv7/omap-common/boot-common.c

@@ -21,6 +21,7 @@
 #include <asm/omap_common.h>
 #include <asm/arch/omap.h>
 #include <asm/arch/mmc_host_def.h>
+#include <asm/arch/sys_proto.h>
 
 /*
  * This is used to verify if the configuration header