V4L/DVB (6471): tuner: i2c_client cannot be part of the tuner struct

The bus-based I2C subsystem allocates the i2c_client struct. So if in order to
be able to convert the tuner to the bus-based I2C API the embedded i2c_client
struct must be removed from the tuner struct and replaced with a pointer.

Signed-off-by: Hans Verkuil <hverkuil@xs4all.nl>
Signed-off-by: Michael Krufky <mkrufky@linuxtv.org>
Signed-off-by: Mauro Carvalho Chehab <mchehab@infradead.org>