doc-rst: linux_tv: Replace reference names to match ioctls

Due to a limitation at the DocBook language, the references
were using lowercase and slashes, instead of the name of the
ioctls. On ReST, make them identical. This will hopefully
help to cleanup the code a little bit.

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