media: camss: Refactor VFE power domain toggling

For Titan ISPs clocks fail to re-enable during vfe_get()
after any vfe has been halted and its corresponding power
domain power has been detached.

Since all of the clocks depend on all of the PDs, per
VFE PD detaching is no option for Gen2 HW.

In order to not have regressions on for Gen1 HW, refactor
the power domain management into hardware version specific
code paths.

Signed-off-by: Robert Foss <robert.foss@linaro.org>
Reviewed-by: Andrey Konovalov <andrey.konovalov@linaro.org>
Signed-off-by: Hans Verkuil <hverkuil-cisco@xs4all.nl>
Signed-off-by: Mauro Carvalho Chehab <mchehab+huawei@kernel.org>