intel: Extend SiP service to support mailbox's RSU

Introduce support for RSU that can be initiated through SMC calls.

Added features as below:
- RSU status
- RSU update
- RSU HPS notify
- RSU get sub-partition

Signed-off-by: Hadi Asyrafi <muhammad.hadi.asyrafi.abdul.halim@intel.com>
Change-Id: I78d5a07688e43da99f03d77dfd45ffb4a78f2e4c
diff --git a/plat/intel/soc/stratix10/bl31_plat_setup.c b/plat/intel/soc/stratix10/bl31_plat_setup.c
index 29f57c4..4c31238 100644
--- a/plat/intel/soc/stratix10/bl31_plat_setup.c
+++ b/plat/intel/soc/stratix10/bl31_plat_setup.c
@@ -16,6 +16,7 @@
 #include <plat/common/platform.h>
 #include <platform_def.h>
 
+#include "socfpga_mailbox.h"
 #include "socfpga_private.h"
 #include "socfpga_reset_manager.h"
 #include "socfpga_system_manager.h"
@@ -115,6 +116,8 @@
 	/* Signal secondary CPUs to jump to BL31 (BL2 = U-boot SPL) */
 	mmio_write_64(PLAT_CPU_RELEASE_ADDR,
 		(uint64_t)plat_secondary_cpus_bl31_entry);
+
+	mailbox_hps_stage_notify(HPS_EXECUTION_STATE_SSBL);
 }
 
 const mmap_region_t plat_stratix10_mmap[] = {