docs(versal2): add AMD Versal Gen 2 documentation

Add information about AMD Versal Gen 2 platform for TF-A Tests and
the build commands.

Change-Id: If1ab592064a6ba39c87e62c32e6e74cd6026caec
Signed-off-by: Maheedhar Bollapalli <maheedharsai.bollapalli@amd.com>
2 files changed