V4L/DVB (9151): dsbr100: Add returns and fix codingstyle for vidioc_s_ctrl

Added return -EBUSY and fixed codingstyle issue

Signed-off-by: Alexey Klimov <klimov.linux@gmail.com>
Signed-off-by: Douglas Schilling Landgraf <dougsland@linuxtv.org>
Signed-off-by: Mauro Carvalho Chehab <mchehab@redhat.com>