soc/intel/common: Add missing SoC common function into SMM library

Modify SMM common code in order to accommodate SKL, CNL, APL, GLK
SOC code.

Change-Id: Ie9f90df3336c1278b73284815b5197400512c1d2
Signed-off-by: Subrata Banik <subrata.banik@intel.com>
Reviewed-on: https://review.coreboot.org/22869
Reviewed-by: Furquan Shaikh <furquan@google.com>
Tested-by: build bot (Jenkins) <no-reply@coreboot.org>

src/soc/intel/apollolake/cpu.c

@@ -238,7 +238,7 @@ static void relocation_handler(int cpu, uintptr_t curr_smbase,
 
 static void post_mp_init(void)
 {
-	smm_southbridge_enable();
+	smm_southbridge_enable(PWRBTN_EN | GBL_EN);
 
 	if (IS_ENABLED(CONFIG_SOC_INTEL_COMMON_BLOCK_SGX))
 		mp_run_on_all_cpus(sgx_configure, 2000);