V4L/DVB (4529): Keep the PID parse bit when resetting the output mode

Matthieu Castet found that with the rewritten dib3000mc-driver the PID-parsing
was handled correctly. This changeset fixes it.
Thanks Matthieu

Signed-off-by: Patrick Boettcher <pb@linuxtv.org>
Signed-off-by: Mauro Carvalho Chehab <mchehab@infradead.org>