WPS: Remove trailing CR from subscription callback URLs

This cleans up the debug log a bit.

Signed-off-by: Jouni Malinen <j@w1.fi>
diff --git a/src/wps/wps_upnp_web.c b/src/wps/wps_upnp_web.c
index 3ec48fc..d5b0b5b 100644
--- a/src/wps/wps_upnp_web.c
+++ b/src/wps/wps_upnp_web.c
@@ -1003,6 +1003,8 @@
 				ret = HTTP_INTERNAL_SERVER_ERROR;
 				goto error;
 			}
+			if (len > 0 && callback_urls[len - 1] == '\r')
+				callback_urls[len - 1] = '\0';
 			continue;
 		}
 		/* SID is only for renewal */