octeontx2-pf: handle otx2_mbox_get_rsp errors in otx2_ethtool.c

Add error pointer check after calling otx2_mbox_get_rsp().

Fixes: 75f36270 ("octeontx2-pf: Support to enable/disable pause frames via ethtool")
Fixes: d0cf9503 ("octeontx2-pf: ethtool fec mode support")
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_ethtool.c

@@ -343,6 +343,11 @@ static void otx2_get_pauseparam(struct net_device *netdev,
 	if (!otx2_sync_mbox_msg(&pfvf->mbox)) {
 		rsp = (struct cgx_pause_frm_cfg *)
 		       otx2_mbox_get_rsp(&pfvf->mbox.mbox, 0, &req->hdr);
+		if (IS_ERR(rsp)) {
+			mutex_unlock(&pfvf->mbox.lock);
+			return;
+		}
+
 		pause->rx_pause = rsp->rx_pause;
 		pause->tx_pause = rsp->tx_pause;
 	}
@@ -1072,6 +1077,11 @@ static int otx2_set_fecparam(struct net_device *netdev,
 
 	rsp = (struct fec_mode *)otx2_mbox_get_rsp(&pfvf->mbox.mbox,
 						   0, &req->hdr);
+	if (IS_ERR(rsp)) {
+		err = PTR_ERR(rsp);
+		goto end;
+	}
+
 	if (rsp->fec >= 0)
 		pfvf->linfo.fec = rsp->fec;
 	else