refactor(plat/ls1043): remove old implementation for platform ls1043

Remove old implementation for Layerscape ls1043a platform, and
will added it back with unified software architecture of all
Layerscape platforms.

Signed-off-by: Jiafei Pan <Jiafei.Pan@nxp.com>
Change-Id: If038c19ab04d70050ec8e6ab2097b1c4f8324e87