net/ixgbe: fix link status

net/ixgbe: fix link status

The link status for 82599eb got from link status register was not
correct, check the enable/disable flag of tx laser when getting the link
status, set the link status down if tx laser disabled since the tx laser
flag could be set correctly when up/down the link status.

Fixes: dc66e5fd01b9 ("net/ixgbe: improve link state check on VF")
Cc: stable@dpdk.org
Signed-off-by: Xiao Zhang <xiao.zhang@intel.com>
Reviewed-by: Wei Zhao <wei.zhao1@intel.com>
Acked-by: Xiaolong Ye <xiaolong.ye@intel.com>