plat: xilinx: zynqmp: Include GICv2 makefile

Update the xilinx platform makefile to include GICv2 makefile
instead of adding the individual files. Updating this change
as per the latest changes done in the commit #1322dc94f7.

Signed-off-by: Venkatesh Yadav Abbarapu <venkatesh.abbarapu@xilinx.com>
Change-Id: I79d8374c47a7f42761d121522b32ac7a5021ede8
1 file changed