V4L/DVB (12386): sms1xxx: fix build warning: unused variable 'board'

Remove the following build warning:

sms-cards.c: In function 'sms_board_event':
sms-cards.c:120: warning: unused variable 'board'

Thanks to Hans Verkuil for pointing this out.

The problem code has been #if 0'd for now, this will likely be
used again in the future, once the event interface is complete.

Cc: Hans Verkuil <hverkuil@xs4all.nl>
Signed-off-by: Michael Krufky <mkrufky@kernellabs.com>
Signed-off-by: Mauro Carvalho Chehab <mchehab@redhat.com>