feat(plat/rcar3): add SYSCEXTMASK bit set/clear in scu_power_up

Added the process of SYSECEXTMASK bit set/clear for following
power Resume/Shutoff flow.

Signed-off-by: Hideyuki Nitta <hideyuki.nitta.jf@hitachi.com>
Signed-off-by: Toshiyuki Ogasahara <toshiyuki.ogasahara.bo@hitachi.com>
Signed-off-by: Yoshifumi Hosoya <yoshifumi.hosoya.wj@renesas.com>
Change-Id: I71ed22840a42e7ab7d87bfd4241eec6f5ddb129b
diff --git a/plat/renesas/common/include/rcar_def.h b/plat/renesas/common/include/rcar_def.h
index 9201b6e..2cd26ed 100644
--- a/plat/renesas/common/include/rcar_def.h
+++ b/plat/renesas/common/include/rcar_def.h
@@ -148,6 +148,8 @@
 #define RCAR_PWRER5		U(0xE61801D4)	/* shutoff/resume error */
 #define RCAR_SYSCISR		U(0xE6180004)	/* Interrupt status     */
 #define RCAR_SYSCISCR		U(0xE6180008)	/* Interrupt stat clear */
+#define RCAR_SYSCEXTMASK	U(0xE61802F8)	/* External Request Mask */
+						/* H3/H3-N, M3 v3.0, M3-N, E3 */
 /* Product register */
 #define RCAR_PRR			U(0xFFF00044)
 #define RCAR_M3_CUT_VER11		U(0x00000010)	/* M3 Ver.1.1/Ver.1.2 */