anv: Get rid of graphics_pipeline_create_info_extra

anv: Get rid of graphics_pipeline_create_info_extra

Now that we no longer have meta, all pipelines get created via the normal
Vulkan pipeline creation mechanics.  There is no more need for this bit of
extra magic data that we've been passing around.

Signed-off-by: Jason Ekstrand <jason@jlekstrand.net>
Reviewed-by: Topi Pohjolainen <topi.pohjolainen@intel.com>