igb: fix a few items where weren't correctly setup for mbx timeout

The mailbox timeout routines need to be updated as they were not correctly
handling the case of a mailbox timeout and could cause issues with long
delays when used.

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>