[media] doc-rst: improve documentation for DTV_FREQUENCY

Make the note better formatted and documented.

Signed-off-by: Mauro Carvalho Chehab <mchehab@s-opensource.com>
This commit is contained in:
Mauro Carvalho Chehab 2016-07-10 09:33:26 -03:00
commit 5632442d6c