arm64: dts: exynos7870-a2corelte: enable display panel support

arm64: dts: exynos7870-a2corelte: enable display panel support

Enable DECON and DSI nodes, and add the compatible display panel and
appropriate panel timings for this device. Also, remove the
simple-framebuffer node in favor of the panel.

This device has a 540x960 Synaptics TD4101 display panel.

Signed-off-by: Kaustabh Chakraborty <kauschluss@disroot.org>
Link: https://patch.msgid.link/20251031-exynos7870-drm-dts-v4-4-c1f77fb16b87@disroot.org
Signed-off-by: Krzysztof Kozlowski <krzysztof.kozlowski@linaro.org>