V4L/DVB (12825): tm6000: I2C reading operations is not reliable on tm6000

tm6000 sometimes can't read from i2c, but this is currently required for
tuner-xc2028 to work.

This patch adds an option to tuner-xc2028 to not rely on i2c reading.

Signed-off-by: Mauro Carvalho Chehab <mchehab@redhat.com>
Signed-off-by: Mauro Carvalho Chehab <mchehab@redhat.com>