anv: Use a switch statement for binding table setup

anv: Use a switch statement for binding table setup

It theoretically could be more efficient but the real point here is that
it's no longer really a matter of dealing with special cases and then
the "real" thing.  The way we're handling binding tables, it's more of a
multi-step process and a switch is more natural.

Reviewed-by: Lionel Landwerlin <lionel.g.landwerlin@intel.com>