igb: check both function bits in status register in wol exception

The ethtool code for enabling Wake on Lan was not correctly checking the
status register bits so as a result ports 0 and 2 were both being allowed
to set WOL to enabled even though it is only supported on the first port
for our adapters.

Signed-off-by: Alexander Duyck <alexander.h.duyck@intel.com>
Signed-off-by: Jeff Kirsher <jeffrey.t.kirsher@intel.com>
Signed-off-by: David S. Miller <davem@davemloft.net>