drm/panel: simple: Add support for PDA 91-00156-A0 panel

PDA 91-00156-A0 5.0 is a 5.0" WVGA TFT LCD panel. This panel with
backlight is found in PDA 5" LCD screen (TM5000 series or AC320005-5).

Signed-off-by: Eugen Hristev <eugen.hristev@microchip.com>
Signed-off-by: Thierry Reding <treding@nvidia.com>
Link: https://patchwork.freedesktop.org/patch/msgid/1547458584-29548-4-git-send-email-eugen.hristev@microchip.com