staging: vt6655: remove unnecessary null check

Remove null check for priv->tx0_bufs, because it can never be null at
this point.
Signed-off-by: Nam Cao <namcaov@gmail.com>
Link: https://lore.kernel.org/r/20220909100650.44609-1-namcaov@gmail.comSigned-off-by: Greg Kroah-Hartman <gregkh@linuxfoundation.org>

drivers/staging/vt6655/device_main.c

@@ -586,7 +586,6 @@ static void device_free_rings(struct vnt_private *priv)
 			  priv->opts.tx_descs[1] * sizeof(struct vnt_tx_desc),
 			  priv->aRD0Ring, priv->pool_dma);
 
-	if (priv->tx0_bufs)
 	dma_free_coherent(&priv->pcid->dev,
 			  priv->opts.tx_descs[0] * PKT_BUF_SZ +
 			  priv->opts.tx_descs[1] * PKT_BUF_SZ +