[media] tuner.h: Make checkpatch.pl happier

Remove some bad whitespaces before tabs and fix the initial
comment to be compliant with Kernel coding style.

Now, the only complains are about long comment lines at the
defines. Those warnings should be ok to be kept.

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