media: video: tegra: apply powergate based on chipset revision

media: video: tegra: apply powergate based on chipset revision

Apply powergate differently depending on chip revision.
Remove dependency of regulator and csi. Enable regulator when any
client asks for power. Previously regulator was enabled only when
csi was enabled.

Bug 855758
Bug 878057

Reviewed-on: http://git-master/r/59369
(cherry picked from commit 88a1aaf5b80f8a76d7f35977a189e641f8c7dcdf)

Reviewed-on: http://git-master/r/60436
(cherry picked from commit ee2605c45b481935173170f6072a32ceb7580e15)

Change-Id: I6341435223b2393f1cf071c3418fa230d8ab4440
Reviewed-on: http://git-master/r/60944
Reviewed-by: Jihoon Bang <jbang@nvidia.com>
Tested-by: Jihoon Bang <jbang@nvidia.com>
Reviewed-by: Dan Willemsen <dwillemsen@nvidia.com>
Rebase-Id: R38b3b9673203a352b62af372e8316b2b703890fb