refactor: do_panic: modify expec string for panic.

Current TF-A code was using spsr_el3 to decide panic from lower or el3
and using that in error string, so tests were assuming its from el2,
the string gets modified to say its from lower el not rely in string el2.

Signed-off-by: Govindraj Raja <govindraj.raja@arm.com>
Change-Id: Ib466c559296fd97e04a421dc49495239e6b7fd5c
diff --git a/expect/timeout.inc b/expect/timeout.inc
index 6d5d0de..c8d9ac1 100644
--- a/expect/timeout.inc
+++ b/expect/timeout.inc
@@ -19,7 +19,7 @@
         message "expected hang, found crash dump"
     }
 
-    "Unhandled Exception from EL" {
+    "Unhandled Exception from lower EL" {
         message "expected hang, found crash dump"
     }