video: tegra: dc: don't pin buffers in propose

video: tegra: dc: don't pin buffers in propose

Don't pin buffers using TEGRA_DC_EXT_SET_PROPOSED_BW. The buffers don't
need to be accessed at all, they only need to be checked if they are
NULL or not. Setting a fake buffer for this call will now be valid, so
simply pass 1 or 0 for the buff_id to indicate which windows are enabled
or disabled.

Change-Id: I940c1ec4a708bfc38c7b5606782859017e51a0d2
Signed-off-by: Jon Mayo <jmayo@nvidia.com>
Reviewed-on: http://git-master/r/383952