ixgbevf: fix link status for PF up/down events

ixgbevf: fix link status for PF up/down events

Current ixgbe VF base driver only really read the status register when:
 - get_link_status is true
 - link reset
 - mailbox timeout.

We only set get_link_status to true when we start the PF/VF, so
following calls to ixgbe_dev_link_update will just keep the old link
status unless the link has been reset.

Because of this behaviour, when the link status of the PF changes after
the VF has been initialized, we do not read the current status register
from the nic and instead we just keep the old link status.

Fix the problem by setting this field to true before calling
ixgbe_check_link function from base driver. We don't need to check after
this call for get_link_status anymore, so remove it.

Signed-off-by: Sergio Gonzalez Monroy <sergio.gonzalez.monroy@intel.com>