[TF-A] GICv3 driver makefile

Hello,

As the prepartion for the series of patches for adding GICv3.1 and GICv4 support, please review and provide your comments for the patch which introduces GICv3 makefile and adds configuration options for the driver. https://review.trustedfirmware.org/c/TF-A/trusted-firmware-a/+/3754

Regards.

Alexei

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