compat.sh: do not filter PSK ciphersuites for GnuTLS if $VERIFY=YES

Signed-off-by: Yanray Wang <yanray.wang@arm.com>
diff --git a/tests/compat.sh b/tests/compat.sh
index 0ee62fc..081640c 100755
--- a/tests/compat.sh
+++ b/tests/compat.sh
@@ -231,7 +231,7 @@
 
     # For GnuTLS client -> mbed TLS server,
     # we need to force IPv4 by connecting to 127.0.0.1 but then auth fails
-    if [ "X$VERIFY" = "XYES" ] && is_dtls "$MODE"; then
+    if is_dtls "$MODE" && [ "X$VERIFY" = "XYES" ] && [ "$TYPE" != "PSK" ]; then
         G_CIPHERS=""
     fi
 }