anv: For pinned BOs, skip relocations, but track bo usage

anv: For pinned BOs, skip relocations, but track bo usage

References to pinned BOs won't need to be relocated at a later
point, so just write the final value of the reference into the bo
directly.

Add a `set` to the relocation lists for tracking dependencies that
were previously tracked by relocations. When a batch is executed, we
add the referenced pinned BOs to the exec list.

v2: - visit bos from the dependency set in a deterministic order (Jason)
v3: - compar => compare, drat (Jason)
    - Reworded commit message, provided by (Jordan)

Reviewed-by: Jordan Justen <jordan.l.justen@intel.com>
Reviewed-by: Jason Ekstrand <jason@jlekstrand.net>