drm/tegra: Implement correct DMA-BUF semantics

DMA-BUF requires that each device that accesses a DMA-BUF attaches to it
separately. To do so the host1x_bo_pin() and host1x_bo_unpin() functions
need to be reimplemented so that they can return a mapping, which either
represents an attachment or a map of the driver's own GEM object.

Signed-off-by: Thierry Reding <treding@nvidia.com>

drm/tegra: Implement syncpoint wait UAPI

Implement new syncpoint wait UAPI. This is different from the
legacy one in taking an absolute timestamp in line with modern
DRM conventions.

Signed-off-by: Mikko Perttunen <mperttunen@nvidia.com>
Signed-off-by: Thierry Reding <treding@nvidia.com>

drm/tegra: Implement syncpoint management UAPI

Implement TegraDRM IOCTLs for allocating and freeing syncpoints.

Signed-off-by: Mikko Perttunen <mperttunen@nvidia.com>
Signed-off-by: Thierry Reding <treding@nvidia.com>

drm/tegra: Implement new UAPI

Implement the non-submission parts of the new UAPI, including
channel management and memory mapping. The UAPI is under the
CONFIG_DRM_TEGRA_STAGING config flag for now.

Signed-off-by: Mikko Perttunen <mperttunen@nvidia.com>
Signed-off-by: Thierry Reding <treding@nvidia.com>