Staging: comedi: gsc_hpdi: Fix style issues

Style cleanup in staging based on Greg's tutorial / checkpatch
Fix 80 char line length (where useful) - includes two changes to code
to make it more logical / readable
Remove {} around single line blocks

Signed-off-by: Dirk Hohndel <hohndel@infradead.org>
Signed-off-by: Greg Kroah-Hartman <gregkh@suse.de>