drm: Add DRM support for tiny LCD displays

tinydrm provides helpers for very simple displays that can use
CMA backed framebuffers and need flushing on changes.

Signed-off-by: Noralf Trønnes <noralf@tronnes.org>
Acked-by: Daniel Vetter <daniel.vetter@ffwll.ch>
Acked-by: Thierry Reding <treding@nvidia.com>

Documentation/gpu/index.rst

@@ -11,6 +11,7 @@ Linux GPU Driver Developer's Guide
    drm-kms-helpers
    drm-uapi
    i915
+   tinydrm
    vga-switcheroo
    vgaarbiter