octeontx2-pf: handle otx2_mbox_get_rsp errors in otx2_common.c

Add error pointer check after calling otx2_mbox_get_rsp().

Fixes: ab58a41 ("octeontx2-pf: cn10k: Get max mtu supported from admin function")
Signed-off-by: Dipendra Khadka <kdipendra88@gmail.com>
Reviewed-by: Simon Horman <horms@kernel.org>
Signed-off-by: Andrew Lunn <andrew@lunn.ch>

drivers/net/ethernet/marvell/octeontx2/nic/otx2_common.c

@@ -1837,6 +1837,10 @@ u16 otx2_get_max_mtu(struct otx2_nic *pfvf)
 	if (!rc) {
 		rsp = (struct nix_hw_info *)
 		       otx2_mbox_get_rsp(&pfvf->mbox.mbox, 0, &req->hdr);
+		if (IS_ERR(rsp)) {
+			rc = PTR_ERR(rsp);
+			goto out;
+		}
 
 		/* HW counts VLAN insertion bytes (8 for double tag)
 		 * irrespective of whether SQE is requesting to insert VLAN