Add null check before dereferencing pointer sgid_attr.ndev
inside function rdma_vlan_dev_vlan_id().
Addresses-Coverity-ID: 
1373979
Signed-off-by: Gustavo A. R. Silva <garsilva@embeddedor.com>
Acked-by: Ram Amrani <Ram.Amrani@cavium.com>
Signed-off-by: Doug Ledford <dledford@redhat.com>
                return rc;
        }
 
-       vlan_id = rdma_vlan_dev_vlan_id(sgid_attr.ndev);
-       if (vlan_id < VLAN_CFI_MASK)
-               has_vlan = true;
-       if (sgid_attr.ndev)
+       if (sgid_attr.ndev) {
+               vlan_id = rdma_vlan_dev_vlan_id(sgid_attr.ndev);
+               if (vlan_id < VLAN_CFI_MASK)
+                       has_vlan = true;
+
                dev_put(sgid_attr.ndev);
+       }
 
        if (!memcmp(&sgid, &zgid, sizeof(sgid))) {
                DP_ERR(dev, "gsi post send: GID not found GID index %d\n",