feat(fvp): add plat API to set and get the DRTM error

Added a platform function to set and get DRTM error.
Also, added a platform function to reset the system.

Signed-off-by: Manish V Badarkhe <Manish.Badarkhe@arm.com>
Change-Id: I471f2387f8c78b21a06af063a6fa02cda3646557
diff --git a/include/plat/common/plat_drtm.h b/include/plat/common/plat_drtm.h
index e9b8d6a..754fa1a 100644
--- a/include/plat/common/plat_drtm.h
+++ b/include/plat/common/plat_drtm.h
@@ -60,4 +60,8 @@
 uint64_t plat_drtm_get_imp_def_dlme_region_size(void);
 uint64_t plat_drtm_get_tcb_hash_features(void);
 
+/* DRTM error handling functions */
+int plat_set_drtm_error(uint64_t error_code);
+int plat_get_drtm_error(uint64_t *error_code);
+
 #endif /* PLAT_DRTM_H */