[media] em28xx: convert tda18212 tuner to I2C client

Used tda18212 tuner is implemented as a I2C driver. Use em28xx
tuner I2C client for tda18212 driver.

Signed-off-by: Antti Palosaari <crope@iki.fi>
Signed-off-by: Mauro Carvalho Chehab <mchehab@osg.samsung.com>