runfvp: handle control-c cleanly

If the script receives control-c, don't display the stack trace.

Change-Id: Id0ebf9476ecd685302723fde6a36c2e899d0f3eb
Signed-off-by: Ross Burton <ross.burton@arm.com>
Signed-off-by: Jon Mason <jon.mason@arm.com>

scripts/runfvp

@@ -164,4 +164,7 @@ def runfvp(args):
         sys.exit(subprocess.run(cli).returncode)
 
 if __name__ == "__main__":
-    runfvp(sys.argv)
+    try:
+        runfvp(sys.argv)
+    except KeyboardInterrupt:
+        pass