staging: comedi: s626: tidy up main source code file

Tidy up the source code in "s626.c" and make it (slightly) more
readable.  It's mostly whitespace changes although some large statements
have been split into smaller statements.  It fixes most of the
checkpatch errors and warnings.
Signed-off-by: Ian Abbott <abbotti@mev.co.uk>
Reviewed-by: H Hartley Sweeten <hsweeten@visionengravers.com>
Signed-off-by: Greg Kroah-Hartman <gregkh@linuxfoundation.org>