ath5k: reduce checkpatch.pl errors

A few changes to reduce checkpatch.pl errors in the ath5k driver.  For
the most part, I only fixed cosmetic things, and left the actual 'code
flow' untouched (hopefully)!

Diff is against wireless-testing HEAD.

Signed-off-by: John Daiker <daikerjohn@gmail.com>
Reviewed-by: Bob Copeland <me@bobcopeland.com>
Acked-by: Nick Kossifidis <mickflemm@gmail.com>
Signed-off-by: John W. Linville <linville@tuxdriver.com>