Staging: comedi: fix comedi_fc.h checkpatch.pl issues.

This resolves all the resolvable checkpatch.pl issues in the
comedi_fc.h file.

Cc: David Schleef <ds@schleef.org>
Cc: Frank Mori Hess <fmhess@users.sourceforge.net>
Cc: Ian Abbott <abbotti@mev.co.uk>
Signed-off-by: Greg Kroah-Hartman <gregkh@suse.de>