intel: Give the batch decoder a callback to ask about state size.

intel: Give the batch decoder a callback to ask about state size.

Given an arbitrary batch, we don't always know what the size of certain
things are, such as how many entries are in a binding table.  But it's
easy for the driver to track that information, so with a simple callback
we can calculate this correctly for INTEL_DEBUG=bat.

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