ice: Don't tx before switchdev is fully configured

There is possibility that ice_eswitch_port_start_xmit might be
called while some resources are still not allocated which might
cause NULL pointer dereference. Fix this by checking if switchdev
configuration was finished.
Reviewed-by: Paul Menzel <pmenzel@molgen.mpg.de>
Reviewed-by: Simon Horman <simon.horman@corigine.com>
Signed-off-by: Wojciech Drewek <wojciech.drewek@intel.com>
Tested-by: Sujai Buvaneswaran <sujai.buvaneswaran@intel.com>
Signed-off-by: Tony Nguyen <anthony.l.nguyen@intel.com>

drivers/net/ethernet/intel/ice/ice_eswitch.c

@@ -331,6 +331,9 @@ ice_eswitch_port_start_xmit(struct sk_buff *skb, struct net_device *netdev)
 	np = netdev_priv(netdev);
 	vsi = np->vsi;
 
+	if (!vsi || !ice_is_switchdev_running(vsi->back))
+		return NETDEV_TX_BUSY;
+
 	if (ice_is_reset_in_progress(vsi->back->state) ||
 	    test_bit(ICE_VF_DIS, vsi->back->state))
 		return NETDEV_TX_BUSY;