V4L/DVB: tuners:tuner-simple Fix warning: variable 'tun' set but not used

Resend due to a whitespace issue I created by mistake.
The below patch fixes a warning message create by gcc 4.6.0

 CC [M]  drivers/media/common/tuners/tuner-simple.o
drivers/media/common/tuners/tuner-simple.c: In function 'simple_set_tv_freq':
drivers/media/common/tuners/tuner-simple.c:548:20: warning: variable 'tun' set but not used

Signed-off-by: Justin P. Mattock <justinmattock@gmail.com>
Signed-off-by: Mauro Carvalho Chehab <mchehab@redhat.com>