net/igb: fix PHY status if PHY reset is not blocked

net/igb: fix PHY status if PHY reset is not blocked

When PHY reset is blocked as is the case when BMC is connected via NC-SI
do not set GO_LINKD bit in PHY power management register in dev_stop as
this will disconnect the PHY. Also, in dev_close clear the GO_LINKD
bit only if PHY reset is not blocked

Fixes: 3af34dec0b41 ("igb: force phy power up/down")
Cc: stable@dpdk.org
Signed-off-by: Shweta Choudaha <shweta.choudaha@att.com>
Reviewed-by: Xiaolong Ye <xiaolong.ye@intel.com>