mmal/vout: Remove bad locking

This removes some bad locking. In fact this lock could cause a deadlock on
shutdown as the lock is held by the main thread when shutting down and this
function might be called as a result of shutting the ports down.
Signed-off-by: Julian Scheel <julian@jusst.de>
Signed-off-by: Rémi Denis-Courmont <remi@remlab.net>

modules/hw/mmal/codec.c

@@ -449,10 +449,8 @@ static picture_t *decode(decoder_t *dec, block_t **pblock)
      * Configure output port if necessary
      */
     if (sys->output_format) {
-        vlc_mutex_lock(&sys->mutex);
         if (change_output_format(dec) < 0)
             msg_Err(dec, "Failed to change output port format");
-        vlc_mutex_unlock(&sys->mutex);
     }
 
     /*