video: tegra: host: Add new ch policy UAPI

video: tegra: host: Add new ch policy UAPI

This patch adds the new map-at-submit channel policy userspace API.
Channel will be assigined on work submit time and unmapped on all
work submit complete for a given device.

Considering this, on channel open only allocate userctx.

Bug 200041935

Change-Id: Ibb75461d458776676fcfb2c407bb75bffbb2b582
Signed-off-by: Shridhar Rasal <srasal@nvidia.com>
Signed-off-by: Arto Merilainen <amerilainen@nvidia.com>
Reviewed-on: http://git-master/r/552327
Reviewed-by: Automatic_Commit_Validation_User
GVS: Gerrit_Virtual_Submit