staging: fsl-dpaa2/ethsw: remove redundant VLAN check

The ethsw_add_vlan() function is already called only when the VLAN is
not yet configured on the switch. Remove the redundant check.

Reported-by: Andrew Lunn <andrew@lunn.ch>
Signed-off-by: Ioana Ciornei <ioana.ciornei@nxp.com>
Link: https://lore.kernel.org/r/1565700187-16048-8-git-send-email-ioana.ciornei@nxp.com


Signed-off-by: Greg Kroah-Hartman <gregkh@linuxfoundation.org>