soc/intel/skylake: Make use of common SMM code for SKL

This patch ensures skylake soc is using common SMM code
from intel common block.

TEST=Build and boot soraka/eve

Change-Id: I8163dc7e18bb417e8c18a12628988959c128b3df
Signed-off-by: Subrata Banik <subrata.banik@intel.com>
Signed-off-by: Brandon Breitenstein <brandon.breitenstein@intel.com>
Reviewed-on: https://review.coreboot.org/22826
Reviewed-by: Furquan Shaikh <furquan@google.com>
Reviewed-by: Aaron Durbin <adurbin@chromium.org>
Tested-by: build bot (Jenkins) <no-reply@coreboot.org>

src/soc/intel/skylake/cpu.c

@@ -38,6 +38,7 @@
 #include <intelblocks/fast_spi.h>
 #include <intelblocks/mp_init.h>
 #include <intelblocks/sgx.h>
+#include <intelblocks/smm.h>
 #include <pc80/mc146818rtc.h>
 #include <soc/cpu.h>
 #include <soc/msr.h>
@@ -436,7 +437,7 @@ static void post_mp_init(void)
 	 * Now that all APs have been relocated as well as the BSP let SMIs
 	 * start flowing.
 	 */
-	southbridge_smm_enable_smi();
+	smm_southbridge_enable(GBL_EN);
 
 	/* Lock down the SMRAM space. */
 #if IS_ENABLED(CONFIG_HAVE_SMI_HANDLER)