ARM: dts: exynos: Add DSI and panel nodes on Arndale

Add to Arndale board: bridge and panel nodes, DSI properties and
regulators required by the bridge.

Signed-off-by: Andrzej Hajda <a.hajda@samsung.com>
Signed-off-by: Maciej Purski <m.purski@samsung.com>
Signed-off-by: Krzysztof Kozlowski <krzk@kernel.org>