arch-mx: add missing include

mxs_wait_mask_set and friends need a declaration
of struct mxs_register_32.

Signed-off-by: Jeroen Hofstee <jeroen@myspectrum.nl>
diff --git a/arch/arm/include/asm/arch-mxs/sys_proto.h b/arch/arm/include/asm/arch-mxs/sys_proto.h
index 09dfc90..062f3de 100644
--- a/arch/arm/include/asm/arch-mxs/sys_proto.h
+++ b/arch/arm/include/asm/arch-mxs/sys_proto.h
@@ -10,6 +10,8 @@
 #ifndef __SYS_PROTO_H__
 #define __SYS_PROTO_H__
 
+#include <asm/imx-common/regs-common.h>
+
 int mxs_reset_block(struct mxs_register_32 *reg);
 int mxs_wait_mask_set(struct mxs_register_32 *reg,
 		       uint32_t mask,