drm/panel: add support for simple-panel description definition using DT

Currently, the only way to add new panel descriptions to the simple panel
driver is to add new entries in the platform_of_match table.

Add support for panel description retrieval from the DT.

Signed-off-by: Boris BREZILLON <boris.brezillon@free-electrons.com>
drm/panel: update simple-panel DT bindings doc with panel desc properties

Document simple-panel description properties and subnodes.

The display-timings definition is the one described in
Documentation/devicetree/bindings/video/display-timing.txt.

Signed-off-by: Boris BREZILLON <boris.brezillon@free-electrons.com>
video: of: display_timing: fix default native-mode setting

Set native mode to the first child node of the display-timings node and not
the first child node of the display-timings parent node.

Signed-off-by: Boris BREZILLON <boris.brezillon@free-electrons.com>
drm: add at91 lcdc support

Signed-off-by: Boris BREZILLON <boris.brezillon@free-electrons.com>
ARM: at91/dt: add lcdc node definition

Signed-off-by: Boris BREZILLON <boris.brezillon@free-electrons.com>
ARM: at91/dt: move sama5d36ek board to simple-panel def

Signed-off-by: Boris BREZILLON <boris.brezillon@free-electrons.com>
ARM: at91/dt: enable lcdc on sama5d36ek board

Signed-off-by: Boris BREZILLON <boris.brezillon@free-electrons.com>