ionic: restore netdev feature bits after reset

When rebuilding the lif after an FLR, be sure to restore the
current netdev features, not do the usual first time feature
init.  This prevents losing user changes to things like TSO
or vlan tagging states.

Fixes: 45b84188

 ("ionic: keep filters across FLR")
Reviewed-by: Brett Creeley <brett.creeley@amd.com>
Signed-off-by: Shannon Nelson <shannon.nelson@amd.com>
Signed-off-by: Paolo Abeni <pabeni@redhat.com>