e1000: clean up the checking logic

The checking logic needed some clean-up work, so we rewrite it by
checking for break first. With that change in place, we can even move
the second check for goto statement outside of the loop.

As this is merely a cleanup, no functional change is involved. The
questionable 'tmp != 0xFF' is intentionally left alone.

Mark Rustad and Alexander Duyck contributed to this patch.

CC: Mark Rustad <mark.d.rustad@intel.com>
CC: Alex Duyck <aduyck@mirantis.com>
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>