arm64: dts: exynos: Add the burst and esc clock frequency properties to DSI node

Add the burst and esc clock frequency properties to the parent (DSI node).
Currently the clock is parsed from the port node, while it should be
taken from the dsi node.

Signed-off-by: Hoegeun Kwon <hoegeun.kwon@samsung.com>
Reviewed-by: Andrzej Hajda <a.hajda@samsung.com>
Reviewed-by: Andi Shyti <andi.shyti@samsung.com>
Signed-off-by: Krzysztof Kozlowski <krzk@kernel.org>