drm/panel: simple: Add Mitsubishi AA070MC01 panel support

The Mitsubishi AA070MC01 is a 7.0" WVGA (800x480) TFT panel working in
8 bit ISP mode (pin 19 "mode" HIGH for 20 pin TFT connector).

Signed-off-by: Lukasz Majewski <lukma@denx.de>
Acked-by: Rob Herring <robh@kernel.org>
Signed-off-by: Thierry Reding <treding@nvidia.com>
Link: https://patchwork.freedesktop.org/patch/msgid/1508537917-1723-1-git-send-email-lukma@denx.de