ixgbe: Release semaphore bits in the right order

The global semaphore bits should be released in the reverse of the
order that they were taken, so correct that.

Signed-off-by: Mark Rustad <mark.d.rustad@intel.com>
Tested-by: Phil Schmitt <phillip.j.schmitt@intel.com>
Signed-off-by: Jeff Kirsher <jeffrey.t.kirsher@intel.com>