mlx4_vnic: always remove child macs in vnic_parent_update remove request

mlx4_vnic: always remove child macs in vnic_parent_update remove request

Child macs are not removed in host admin vnics once the connection
is lost with BX. This caused a loss of connectivity for child vnics
in case of connection restored with the BX, since the BX is not
aware of the old child macs.

Solution is to always remove child macs when vnic_paren_update is
called with remove request.

Signed-off-by: Saeed Mahameed <saeedm@mellanox.com>
(Ported from Mellanox OFED 2.4)

Signed-off-by: Mukesh Kacker <mukesh.kacker@oracle.com>