feat(zynqmp): enable ENABLE_LTO flag

Enabling Link Time Optimization in platform.mk for AMD-Xilinx
ZynqMP platform optimizes TF-A size.
With ENABLE_LTO=0, the release bl31.elf size is 86098.
With ENABLE_LTO=1, the release bl31.elf size reduces to 81866.
The size difference in OCM is 4232 bytes, saving up to 4KB.

Signed-off-by: Prasad Kummari <prasad.kummari@amd.com>
Change-Id: I6d5001a9ac250e3a87b958e9b665962a917265d6
1 file changed