mmc: Add runtime and system-wide PM to the TMIO MMC driver

Add runtime and system-wide power management to the TMIO MMC driver
in PIO and DMA modes, allowing it to properly save and restore its
state during system suspend. Runtime PM is very crude ATM, because
the controller has to be powered on all the time to detect card
hotplug events.

Signed-off-by: Guennadi Liakhovetski <g.liakhovetski@gmx.de>
Signed-off-by: Chris Ball <cjb@laptop.org>