mfd: tc6393 cleanup and update

This patchset cleans up the TC6393XB support.

* Add provision for the MMC subdevice
* Disable / enable clocks on suspend / resume
* Remove fragments of badly merged code (eg. linux/fb include etc.)
* Use a device specific clock name to break dependancy on ARM/PXA2XX
* Drop unnecessary resource names
* Switch to tmio_io* accessors

Signed-off-by: Ian Molton <spyro@f2s.com>
Signed-off-by: Samuel Ortiz <sameo@openedhand.com>