octeontx2-pf: Send UP messages to VF only when VF is up.

When PF sending link status messages to VF, it is possible
that by the time link_event_task work function is executed
VF might have brought down. Hence before sending VF link
status message check whether VF is up to receive it.

Fixes: ad513ed9 ("octeontx2-vf: Link event notification support")
Signed-off-by: Subbaraya Sundeep <sbhatta@marvell.com>
Signed-off-by: David S. Miller <davem@davemloft.net>