anv: add fake sparse support

anv: add fake sparse support

Some DX12 games require sparse resource support but don't
actually use sparse resources. Add a way to make these games work
while we still don't have sparse resources fully working on every
KMD backend.

When fake_sparse=true, anv advertises sparse resource support
despite lacking full support.

Based-on-patch-by: Paulo Zanoni <paulo.r.zanoni@intel.com>
Reviewed-by: Lionel Landwerlin <lionel.g.landwerlin@intel.com>
Part-of: <https://gitlab.freedesktop.org/mesa/mesa/-/merge_requests/24046>