This adds support for the RTL9300 and RTL9310 I2C controller.
The controller implements the SMBus protocol for SMBus transfers
over an I2C bus. The driver supports selecting one of the 2 possible
SCL pins and any of the 8 possible SDA pins. Bus speeds of
100kHz (standard speed) and 400kHz (high speed I2C) are supported.
Signed-off-by: Birger Koblitz <git@birger-koblitz.de>
