octeontx2-af: Fix possible null pointer dereference.

This patch fixes possible null pointer dereference in files
"rvu_debugfs.c" and "rvu_nix.c"

Fixes: 8756828a ("octeontx2-af: Add NPA aura and pool contexts to debugfs")
Fixes: 9a946def ("octeontx2-af: Modify nix_vtag_cfg mailbox to support TX VTAG entries")
Signed-off-by: Rakesh Babu Saladi <rsaladi2@marvell.com>
Signed-off-by: Subbaraya Sundeep <sbhatta@marvell.com>
Signed-off-by: Sunil Goutham <sgoutham@marvell.com>
Signed-off-by: David S. Miller <davem@davemloft.net>

drivers/net/ethernet/marvell/octeontx2/af/rvu_debugfs.c

@@ -578,7 +578,7 @@ static ssize_t rvu_dbg_qsize_write(struct file *filp,
 	if (cmd_buf)
 		ret = -EINVAL;
 
-	if (!strncmp(subtoken, "help", 4) || ret < 0) {
+	if (ret < 0 || !strncmp(subtoken, "help", 4)) {
 		dev_info(rvu->dev, "Use echo <%s-lf > qsize\n", blk_string);
 		goto qsize_write_done;
 	}

drivers/net/ethernet/marvell/octeontx2/af/rvu_nix.c

@@ -2507,6 +2507,9 @@ static void nix_free_tx_vtag_entries(struct rvu *rvu, u16 pcifunc)
 		return;
 
 	nix_hw = get_nix_hw(rvu->hw, blkaddr);
+	if (!nix_hw)
+		return;
+
 	vlan = &nix_hw->txvlan;
 
 	mutex_lock(&vlan->rsrc_lock);