[media] coda: Add runtime pm support

This patch allows to use the runtime pm and generic pm domain frameworks
to completely gate power to the VPU if it is unused. This functionality
is available on i.MX6.

Signed-off-by: Philipp Zabel <p.zabel@pengutronix.de>
Signed-off-by: Kamil Debski <k.debski@samsung.com>
Signed-off-by: Mauro Carvalho Chehab <m.chehab@samsung.com>