intel/fsp_baytrail: Include header for "southcluster_smm_save_gpio_route"

Fix the error 'implicit declaration of function
"southcluster_smm_save_gpio_route"', when SMM module is added.

Change-Id: Ia050ab7e2b036541537b645d3fe4dc747cd1dff8
Signed-off-by: Kayalvizhi Dhandapani <kayalvizhid@ami.com>
Reviewed-on: http://review.coreboot.org/7024
Reviewed-by: Paul Menzel <paulepanter@users.sourceforge.net>
Tested-by: build bot (Jenkins)
Reviewed-by: Martin Roth <gaumless@gmail.com>

src/soc/intel/fsp_baytrail/gpio.c

@@ -21,6 +21,7 @@
 #include <console/console.h>
 #include <baytrail/gpio.h>
 #include <baytrail/pmc.h>
+#include <baytrail/smm.h>
 
 /* GPIO-to-Pad LUTs */
 static const u8 gpncore_gpio_to_pad[GPNCORE_COUNT] =