ARM: dts: imx6ull-colibri: move u-boot specific node

1. Move aliases and legacy lcdif node to the u-boot specific dts include.
2. Provide proper display timings, as in the downstream Toradex kernel
[1].

[1]: https://git.toradex.com/cgit/linux-toradex.git/tree/arch/arm/boot/dts/imx6ull-colibri-eval-v3.dtsi?h=toradex_4.9-2.3.x-imx#n183


Signed-off-by: Igor Opaniuk <igor.opaniuk@toradex.com>