video: Runtime PM for SuperH Mobile LCDC

This patch modifies the SuperH Mobile LCDC framebuffer driver
to support Runtime PM. The driver is using the functions

 - pm_runtime_get_sync()
 - pm_runtime_put_sync()

to inform the bus code if the hardware is idle or not. If the
hardware is idle then the bus code may call the runtime dev_pm_ops
callbacks to save and restore state. pm_runtime_resume() is used
to allow the driver to access the hardware from probe().

Signed-off-by: Magnus Damm <damm@igel.co.jp>
Signed-off-by: Paul Mundt <lethal@linux-sh.org>