drivers/i2c: add i2c driver on it8xxx2 platform

This commit is about the it8xxx2 i2c master driver which
includes six SMBus channels. The enhanced channel i2c3,
i2c4, i2c5 are controller which are designed to support
the I2C protocol.

Signed-off-by: Tim Lin <tim2.lin@ite.corp-partner.google.com>
10 files changed