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/plat/arm/board/fvp/fvp_err.c b/plat/arm/board/fvp/fvp_err.c
index 1f9f0dd..244659a 100644
--- a/plat/arm/board/fvp/fvp_err.c
+++ b/plat/arm/board/fvp/fvp_err.c
@@ -29,3 +29,15 @@
 	for (;;)
 		wfi();
 }
+
+void __dead2 plat_arm_system_reset(void)
+{
+	/* Write the System Configuration Control Register */
+	mmio_write_32(V2M_SYSREGS_BASE + V2M_SYS_CFGCTRL,
+		      V2M_CFGCTRL_START |
+		      V2M_CFGCTRL_RW |
+		      V2M_CFGCTRL_FUNC(V2M_FUNC_REBOOT));
+	wfi();
+	ERROR("FVP System Reset: operation not handled.\n");
+	panic();
+}