nitrogen6x: display: add support lvds jeida screen

Add support for Boundary Devices 7" and 10.1" 1280x800 displays with
integrated FocalTech ft5x06 10-point touch controller.

Because they share the touch controller with the 1024x600 displays,
auto-detection is disabled and you must explicitly set the 'panel'
environment variable:

        U-Boot > setenv panel LDB-WXGA
        U-Boot > saveenv && reset

Signed-off-by: Robert Winkler <robert.winkler@boundarydevices.com>
Signed-off-by: Eric Nelson <eric.nelson@boundarydevices.com>