V4L/DVB (4846): Create new lgh06xf atsc tuner module

This patch creates a new atsc tuner module for the LG TDVS-H06xF ATSC tuners,
called lgh06xf.  The purpose of this change is to reduce some duplicated
code, and to allow the lgh06xf tuner code to take advantage of dvb_attach().
As a side effect, the dependency of dvb-bt8xx on dvb-pll has been removed,
since the lgh06xf module itself will use dvb-pll, while remaining optional
for the dvb-bt8xx driver through the use of DVB_FE_CUSTOMISE
Acked-by: Andrew de Quincey <adq_dvb@lidskialf.net>

Signed-off-by: Michael Krufky <mkrufky@linuxtv.org>
Signed-off-by: Mauro Carvalho Chehab <mchehab@infradead.org>