mfd: Adopt mfd_data in 88pm860x input driver

Copy 88pm860x platform data into different mfd_data structure for
onkey/touch/codec/power driver. So move the identification of
device node from those drivers to mfd driver.

Signed-off-by: Haojian Zhuang <haojian.zhuang@marvell.com>
Signed-off-by: Samuel Ortiz <sameo@linux.intel.com>