anv/cmd_buffer: add the pipeline layout to the pipeline state

anv/cmd_buffer: add the pipeline layout to the pipeline state

We need to access the pipeline layout to compute correct dynamic
offsets for dyamic UBO/SSBO descriptors when we emit draw commands.
Instead of taking it from the pipeline object, store the layout
in the command buffer pipeline state.

Suggested-by: Jason Ekstrand <jason@jlekstrand.net>
Reviewed-by: Jason Ekstrand <jason@jlekstrand.net>