media: venus: redesign clocks and pm domains control

Redesign core (vcodec) clock control to give the venus core more
freedom to control them in order to make possible to use core
selection feature on Venus IP v4.

Move all clock and pmdomain functions in separate file and abstract
power control with common operations per Venus IP version.

Signed-off-by: Stanimir Varbanov <stanimir.varbanov@linaro.org>
Signed-off-by: Mauro Carvalho Chehab <mchehab+huawei@kernel.org>