anv: add support for INTEL_DEBUG=bat

anv: add support for INTEL_DEBUG=bat

As requested by Ken ;)

v2: Also decode simple batches (Caio)
    Fix u_vector usage issues (Lionel)

v3: Make binding/instruction/state/surface available (Lionel)

v4: Going through device pools for simple batches (Lionel)
    Centralize search BO callbacks into anv_device.c (Lionel)

v5: Clear decoded batch buffer var after use (Caio)

Signed-off-by: Lionel Landwerlin <lionel.g.landwerlin@intel.com>
Reviewed-by: Caio Marcelo de Oliveira Filho <caio.oliveira@intel.com>