gpio/ml_ioh_gpio: ML7213 GPIO driver

ML7213 is a companion chip for Intel Atom E6xx series.  This driver can be
used for OKI SEMICONDUCTOR ML7213 IOH(Input/Output Hub) which is for
IVI(In-Vehicle Infotainment) use.  This driver can access the IOH's GPIO
device.

Signed-off-by: Tomoya MORINAGA <tomoya-linux@dsn.okisemi.com>
Cc: Samuel Ortiz <sameo@linux.intel.com>
Cc: Rabin Vincent <rabin.vincent@stericsson.com>
Cc: Marc Zyngier <maz@misterjones.org>
Cc: Linus Walleij <linus.walleij@stericsson.com>
Cc: Mark Brown <broonie@opensource.wolfsonmicro.com>
Signed-off-by: Andrew Morton <akpm@linux-foundation.org>
Signed-off-by: Linus Torvalds <torvalds@linux-foundation.org>