sif: vlink connect is now enabled by default

sif: vlink connect is now enabled by default

This fix makes default link failover behaviour compatible with existing
mellanox CX3. Internal link status (PortState) will now follow external
link status (PortState) by default.

Driver feature mask SIFF_vlink_disconnect may be used to set default
behaviour to "vlink connect"=disabled.

Orabug: 24445370

Signed-off-by: Harald Høeg <harald.hoeg@oracle.com>
Reviewed-by: Håkon Bugge <haakon.bugge@oracle.com>
Signed-off-by: Knut Omang <knut.omang@oracle.com>