ENGR00240987: ARM: dts: enable LDB and LCD support for imx6qdl-sabresd

ENGR00240987: ARM: dts: enable LDB and LCD support for imx6qdl-sabresd

This is a fast-forward porting of LDB and LCD DTS changes from 3.5.7
kernel.

Along with the changes, the "&ldb" node gets removed from imx6q.dtsi,
since it's only used by community kernel and will conflict with our
internal LDB bindings.

While adding alias for ipu in imx6qdl.dtsi, it also sorts all those
aliases alphabetically.

Signed-off-by: Shawn Guo <shawn.guo@freescale.com>