anv/apply_pipeline_layout: Add to the bind map instead of replacing it

anv/apply_pipeline_layout: Add to the bind map instead of replacing it

This commit makes three changes.  One is to only walk the descriptors once
and set bind map sizes at the same time as filling out the entries.  The
second is to make the pass additive so that we can put stuff in the bind
map before applying the pipeline layout.  Third, we switch to using
designated initializers.

Reviewed-by: Timothy Arceri <tarceri@itsqueeze.com>
Reviewed-by: Lionel Landwerlin <lionel.g.landwerlin@intel.com>