pch_dma: support new device ML7213 IOH

Support new device OKI SEMICONDUCTOR's ML7213 IOH(Input/Output Hub) which is for
IVI(In-Vehicle Infotainment) use.
The ML7213 is companion chip for Intel Atom E6xx series.
The ML7213 is completely compatible for Intel EG20T PCH.

Signed-off-by: Tomoya MORINAGA <tomoya-linux@dsn.okisemi.com>
Signed-off-by: Dan Williams <dan.j.williams@intel.com>