V4L/DVB (6948): HVR950 requires additional settings for audio to properly work

Thanks to Markus Rechberger <mrechberger@gmail.com> for retriving those
commands.

Also, MTS firmware is required for audio to work on HVR950.

Signed-off-by: Mauro Carvalho Chehab <mchehab@infradead.org>