test(realm): extend ripas tests for planes

Test that accessing page with RIPAS=EMPTY from
Plane N causes plane exit to P0.

Change-Id: Ic57f049d0fa0140630aa7bfc0702a2dc729967a8
Signed-off-by: Shruti Gupta <shruti.gupta@arm.com>
diff --git a/realm/include/realm_rsi.h b/realm/include/realm_rsi.h
index 06f857f..7139023 100644
--- a/realm/include/realm_rsi.h
+++ b/realm/include/realm_rsi.h
@@ -65,6 +65,8 @@
 	RSI_ERROR_COUNT
 } rsi_status_t;
 
+#define RSI_EXIT_SYNC	0U
+
 /* Size of Realm Personalization Value */
 #define RSI_RPV_SIZE			64U