octeontx2-pf: Add missing mutex lock in otx2_get_pauseparam

All the mailbox messages sent to AF needs to be guarded
by mutex lock. Add the missing lock in otx2_get_pauseparam
function.

Fixes: 75f3627 ("octeontx2-pf: Support to enable/disable pause frames via ethtool")
Signed-off-by: Subbaraya Sundeep <sbhatta@marvell.com>
Reviewed-by: Simon Horman <horms@kernel.org>
Signed-off-by: David S. Miller <davem@davemloft.net>

Author: Subbaraya Sundeep

drivers/net/ethernet/marvell/octeontx2/nic/otx2_ethtool.c

@@ -334,16 +334,20 @@ static void otx2_get_pauseparam(struct net_device *netdev,
 	if (is_otx2_lbkvf(pfvf->pdev))
 		return;
 
+	mutex_lock(&pfvf->mbox.lock);
 	req = otx2_mbox_alloc_msg_cgx_cfg_pause_frm(&pfvf->mbox);
-	if (!req)
+	if (!req) {
+		mutex_unlock(&pfvf->mbox.lock);
 		return;
+	}
 
 	if (!otx2_sync_mbox_msg(&pfvf->mbox)) {
 		rsp = (struct cgx_pause_frm_cfg *)
 		       otx2_mbox_get_rsp(&pfvf->mbox.mbox, 0, &req->hdr);
 		pause->rx_pause = rsp->rx_pause;
 		pause->tx_pause = rsp->tx_pause;
 	}
+	mutex_unlock(&pfvf->mbox.lock);
 }
 
 static int otx2_set_pauseparam(struct net_device *netdev,