samsung: i2c: Split the high-speed I2C code into a new driver

Now that driver model is used for I2C on all boards, we can split the
high-speed code into its own driver. There is virtually no common code,
and this significantly reduces confusion.

Signed-off-by: Simon Glass <sjg@chromium.org>
Acked-by: Heiko Schocher <hs@denx.de>