feat: spm helper functions for MP tests

Added two helper functions to help with SPM tests in a MP setup.
- spm_core_sp_init: to initialize an SP in a given core.
- get_current_core_id: to get the current core ID.

Signed-off-by: J-Alves <joao.alves@arm.com>
Change-Id: Iad10d43f258f5ed05ce52b87c94a9333c228f26d
diff --git a/include/runtime_services/spm_common.h b/include/runtime_services/spm_common.h
index 2393dc6..f4b5a75 100644
--- a/include/runtime_services/spm_common.h
+++ b/include/runtime_services/spm_common.h
@@ -7,10 +7,13 @@
 #ifndef SPM_COMMON_H
 #define SPM_COMMON_H
 
-#include <ffa_helpers.h>
+#include <plat/common/platform.h>
+
 #include <stdint.h>
 #include <string.h>
 
+#include <ffa_helpers.h>
+
 /* Hypervisor ID at physical FFA instance */
 #define HYP_ID          (0)
 /* SPMC ID */