drm/panel: simple-panel: Add panel picker support.

This patch adds panel picker support to simple-panel.

The idea of panel picker is to select the correct panel timings if it
supports probing edid via DDC bus, edid contains manufacture ID
and Manufacturer product code, so it can match against the panel_picker
entries to get the correct panel timings.

From DT point of view the panel picker uses generic compatible string
"panel-simple", keeping the panel specific compatible strings still
supported.

Panels can be static entry in the DT, but practically development boards
like IFC6410 where developers can connect any LVDS panel which makes it
difficult to maintian the dt support for those panels in dts file.
With this dynamic probing via panel picker makes it easy to support such
use-cases.
This patch also adds panel presence detection based, if there is no
panel detected or panel picker could not find the panel then the driver
would mark the panel DT node as disabled so that the drm driver would
be able to take right decision based on that panel node status.

Signed-off-by: Srinivas Kandagatla <srinivas.kandagatla@linaro.org>