[media] e4000: convert DVB tuner to I2C driver model

Driver conversion from proprietary DVB tuner model to more
general I2C driver model.

Cc: Jean Delvare <khali@linux-fr.org>
Signed-off-by: Antti Palosaari <crope@iki.fi>
Signed-off-by: Mauro Carvalho Chehab <m.chehab@samsung.com>