video: tegra: nvavp: Add a clock request ioctl

Add nvavp_force_clock_stay_on ioctl which provides way for user-mode driver
to request the VDE/BSEV clocks. This change is to fix a hang during DRM
session close. The AVP driver may have already turned
the clocks off since playback was paused prior to session teardown. This
situation can cause the OTF driver on secure side to hang if the VDE/BSEV
clocks are not explicitly enabled prior to calling session terminate.

Bug 960130
Bug 961015
Bug 979102

Change-Id: I3c09a6766f50a01ed04fbfd03e723ad9e978909f
Reviewed-on: http://git-master/r/102024
Reviewed-by: Prajakta Gudadhe <pgudadhe@nvidia.com>
Tested-by: Prajakta Gudadhe <pgudadhe@nvidia.com>

Conflicts:
	drivers/media/video/tegra/nvavp/nvavp_dev.c