e1000e: clean up the local variable

The local variable 'ret' doesn't serve much purpose so we might as well
clean it up.

Signed-off-by: Jean Sacren <sakiwit@gmail.com>
Tested-by: Aaron Brown <aaron.f.brown@intel.com>
Signed-off-by: Jeff Kirsher <jeffrey.t.kirsher@intel.com>