V4L/DVB (12560): Fix a number of EXPORT_SYMBOL warnings

Make Checkpatch tool happy:

-:2349: WARNING: EXPORT_SYMBOL(foo); should immediately follow its function/variable

On all cases, it were just a blank line at the wrong place. Yet, fixing it is trivial

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