i2c-eg20t: support new device OKI SEMICONDUCTOR ML7213 IOH

Support new device OKI SEMICONDUCTOR ML7213 IOH.
The ML7213 which is for IVI(In-Vehicle Infotainment) is a companion
chip for the Atom E6xx series and compatible with the Intel EG20T
PCH.

Signed-off-by: Tomoya MORINAGA <tomoya-linux@dsn.okisemi.com>
Signed-off-by: Ben Dooks <ben-linux@fluff.org>