chore(xilinx): update warning message

Update the Warning message to be more informative
about the warning being printed.

Change-Id: I923dc5dd760908844d5e1ac8542fd1b04c9f0af5
Signed-off-by: Akshay Belsare <akshay.belsare@amd.com>
diff --git a/plat/xilinx/common/plat_startup.c b/plat/xilinx/common/plat_startup.c
index df3a39f..f45c9f0 100644
--- a/plat/xilinx/common/plat_startup.c
+++ b/plat/xilinx/common/plat_startup.c
@@ -231,7 +231,8 @@
 		target_el = get_xbl_el(&HandoffParams->partition[i]);
 		if ((target_el == XBL_FLAGS_EL3) ||
 		    (target_el == XBL_FLAGS_EL0)) {
-			WARN("BL31: invalid exception level (%i)\n", target_el);
+			WARN("BL31: invalid target exception level(%i)\n",
+			     target_el);
 			continue;
 		}