This patch is to split image makefile per subtarget.
The ARMv7 subtarget will be added in the future.
It will be not convinient if only one makefile is used
for several subtargets management and future development.
This patch also dropped 32-bit Traverse LS1043-S since
Traverse only intended to support 64-bit and the 32-bit
compile now had an issue.
Signed-off-by: Yangbo Lu <yangbo.lu@nxp.com>
