Staging: comedi: addi_common.c: checkpatch.pl fixes

checkpatch.pl style fixes:
- Broken license text into 80 char lines
- fixed two space before tab issues
- Removed unnecessary braces from if-else

Signed-off-by: Lijo Antony <lijo.kernel@gmail.com>
Signed-off-by: Greg Kroah-Hartman <gregkh@linuxfoundation.org>