net/bnxt: fix VLAN add when port is stopped

Driver destroys the vnic when the port is brought down.
When user tries to add a vlan when port is stopped, driver
issues HWRM command to FW with invalid vnic_id and it fails.

Fixed to return an error while setting vlan when port is
not started.

Fixes: b4e190d ("net/bnxt: fix MAC/VLAN filter allocation")
Cc: stable@dpdk.org

Signed-off-by: Kalesh AP <kalesh-anakkur.purayil@broadcom.com>
Reviewed-by: Venkat Duvvuru <venkatkumar.duvvuru@broadcom.com>
Reviewed-by: Ajit Khaparde <ajit.khaparde@broadcom.com>

drivers/net/bnxt/bnxt_ethdev.c

@@ -2082,6 +2082,11 @@ static int bnxt_vlan_filter_set_op(struct rte_eth_dev *eth_dev,
 	if (rc)
 		return rc;
 
+	if (!eth_dev->data->dev_started) {
+		PMD_DRV_LOG(ERR, "port must be started before setting vlan\n");
+		return -EINVAL;
+	}
+
 	/* These operations apply to ALL existing MAC/VLAN filters */
 	if (on)
 		return bnxt_add_vlan_filter(bp, vlan_id);