um: Do not unlock mutex that is not hold.

Return error instead of trying to unlock a mutex that is not hold.
Signed-off-by: Daniel Walter <dwalter@google.com>
Reviewed-by: Anton Ivanov <anton.ivanov@cambridgegreys.com>
Acked-by: Anton Ivanov <anton.ivanov@cambridgegreys.com>
Signed-off-by: Richard Weinberger <richard@nod.at>

arch/um/drivers/ubd_kern.c

@@ -276,14 +276,14 @@ static int ubd_setup_common(char *str, int *index_out, char **error_out)
 		str++;
 		if(!strcmp(str, "sync")){
 			global_openflags = of_sync(global_openflags);
-			goto out1;
+			return err;
 		}
 
 		err = -EINVAL;
 		major = simple_strtoul(str, &end, 0);
 		if((*end != '\0') || (end == str)){
 			*error_out = "Didn't parse major number";
-			goto out1;
+			return err;
 		}
 
 		mutex_lock(&ubd_lock);