video: tegra: dc: Support for pre power-off actions

video: tegra: dc: Support for pre power-off actions

Part of panel settings need to be done before/after pixel clock
is disabled. Add support for these actions to meet panel
spec.

bug 976081

Signed-off-by: Ken Chang <kenc@nvidia.com>
Reviewed-on: http://git-master/r/102542
Reviewed-by: Lokesh Pathak <lpathak@nvidia.com>
Tested-by: Lokesh Pathak <lpathak@nvidia.com>
(cherry picked from commit dcecdc64d4d0fd4d9f69df52c9d200dfbf1dd7fc)

Change-Id: Ibfede68d67a4815156f73c2d1cdca90f3f771755
Reviewed-on: http://git-master/r/110296
Reviewed-by: Simone Willett <swillett@nvidia.com>
Tested-by: Simone Willett <swillett@nvidia.com>
Rebase-Id: Rf7e4c33a9f956e74a6a24bb8dae948db91bf016f