V4L/DVB (3935): Add missing pll gate control calls

I'd missed some of these out, breaking the av7110 tuning. I then checked for
more and added them in where necessary. They may not actually be necessary
in all these locations, but if not, they'll simply have no effect.
Add small delay to stv0299 pll gate control to fix tuning problems.

Signed-off-by: Andrew de Quincey <adq_dvb@lidskialf.net>
Signed-off-by: Mauro Carvalho Chehab <mchehab@infradead.org>