ARM: exynos_defconfig: Enable options for display panel support

Many Exynos devices have a display panel. Most of them just have
a simple panel while others have more complex configurations that
requires an embedded DisplayPort (eDP) to LVDS bridges.

This patch enables the following features to be built in the kernel
image to support both setups:

- Direct Rendering Manager (DRM)
- DRM bridge registration and lookup framework
- Parade ps8622/ps8625 eDP/LVDS bridge
- NXP ptn3460 eDP/LVDS bridge
- Exynos Fully Interactive Mobile Display controller (FIMD)
- Panel registration and lookup framework
- Simple panels
- Backlight & LCD device support

Signed-off-by: Javier Martinez Canillas <javier.martinez@collabora.co.uk>
Tested-by: Kevin Hilman <khilman@linaro.org>
Signed-off-by: Kukjin Kim <kgene@kernel.org>