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/platform.h b/include/plat/common/platform.h
index 58e08d4..c90441c 100644
--- a/include/plat/common/platform.h
+++ b/include/plat/common/platform.h
@@ -128,6 +128,7 @@
 void plat_crash_console_flush(void);
 void plat_error_handler(int err) __dead2;
 void plat_panic_handler(void) __dead2;
+void plat_system_reset(void) __dead2;
 const char *plat_log_get_prefix(unsigned int log_level);
 void bl2_plat_preload_setup(void);
 int plat_try_next_boot_source(void);