Add FB modifiers to allow user-space to specify that a surface is in one
of the two tiling formats supported by Tegra chips, and add support in
the tegradrm driver to handle them properly. This is necessary for the
display controller to directly display buffers generated by the GPU.

This feature is intended to replace the dedicated IOCTL enabled
by TEGRA_STAGING and to provide a non-staging alternative to that
solution.
Signed-off-by: Alexandre Courbot <acourbot@nvidia.com>
Acked-by: Daniel Vetter <daniel@ffwll.ch>
Signed-off-by: Thierry Reding <treding@nvidia.com>