[media] dvb-frontends/stv0367: make full reinit on set_frontend() optional

[media] dvb-frontends/stv0367: make full reinit on set_frontend() optional

Every time dvb_frontend_ops.set_frontend() is called, an almost full reinit
of the demodulator will be performed. While this might cause a slight delay
when switching channels due to all involved tables being rewritten, it can
even be dangerous in certain causes in that the demod may lock up and
requires to be powercycled (this can happen on Digital Devices hardware).
So this adds a flag if it should be done, and to not change behaviour with
existing card support, it'll be enabled in all cases.

Signed-off-by: Daniel Scheller <d.scheller@gmx.net>
Signed-off-by: Mauro Carvalho Chehab <mchehab@s-opensource.com>