media: gl861: re-implement I2C adapter logic

Device I2C adapter is capable of writing and reading large messages.
For I2C writes there is 2 methods: simple for max 2 byte messages and
usb_control_msg() with payload data for larger I2C messages. Add I2C
adapter logic which selects suitable method according to message size.
Add also support for plain I2C read.

Cc: Akihiro TSUKADA <tskd08@gmail.com>
Signed-off-by: Antti Palosaari <crope@iki.fi>
Signed-off-by: Sean Young <sean@mess.org>
Signed-off-by: Mauro Carvalho Chehab <mchehab+samsung@kernel.org>