net: enetc: fix check for allocation failure

This was supposed to be a check for if dma_alloc_coherent() failed
but it has a copy and paste bug so it will not work.

Fixes: fb8629e2 ("net: enetc: add support for software TSO")
Signed-off-by: Dan Carpenter <dan.carpenter@oracle.com>
Reviewed-by: Ioana Ciornei <ioana.ciornei@nxp.com>
Link: https://lore.kernel.org/r/20211013080456.GC6010@kiliSigned-off-by: Jakub Kicinski <kuba@kernel.org>

drivers/net/ethernet/freescale/enetc/enetc.c

@@ -1767,8 +1767,10 @@ static int enetc_alloc_txbdr(struct enetc_bdr *txr)
 					      txr->bd_count * TSO_HEADER_SIZE,
 					      &txr->tso_headers_dma,
 					      GFP_KERNEL);
-	if (err)
+	if (!txr->tso_headers) {
+		err = -ENOMEM;
 		goto err_alloc_tso;
+	}
 
 	txr->next_to_clean = 0;
 	txr->next_to_use = 0;