V4L/DVB (6158): Fix MT2131 tuner lock status problem

The mt2131 tuner reports lock even when the hardware should not
lock. This patch allows the s5h1409 demodulator to be configured to query
either the tuner driver for status, or the demodulator status when the
application requests lock status. This avoids returning false CARRIER
and/or SIGNAL lock status.

S5H1409 and MT2131 drivers.  This is the remainder of the changeset, which
only touches cx23885-dvb.c

Signed-off-by: Steven Toth <stoth@hauppauge.com>
Signed-off-by: Michael Krufky <mkrufky@linuxtv.org>
Signed-off-by: Mauro Carvalho Chehab <mchehab@infradead.org>