[media] dib3000mc: Fix indentation

drivers/media/dvb-frontends/dib3000mc.c:134 dib3000mc_setup_pwm_state() warn: inconsistent indenting
drivers/media/dvb-frontends/dib3000mc.c:144 dib3000mc_setup_pwm_state() warn: inconsistent indenting
drivers/media/dvb-frontends/dib3000mc.c:420 dib3000mc_sleep() warn: inconsistent indenting
drivers/media/dvb-frontends/dib3000mc.c:453 dib3000mc_set_channel_cfg() warn: inconsistent indenting

The last one is actually due to a commented code. Let's rework
it, in order to remove the sparse warning without removing the
dead code, as it may be useful in the future.

Signed-off-by: Mauro Carvalho Chehab <mchehab@osg.samsung.com>