emit_depthbuffer refactor: rearrange args to do_stuff
emit_depthbuffer refactor: move depth stall flushes into do_stuff
emit_depthbuffer refactor: modify pre-gen7 state atom to look like gen7
emit_depthbuffer refactor: Virtualize do_stuff
!UPSTREAM: Hacky fix for Gen5 depthstencil-render-miplevels stencil-only test.  TODO: think through, test thoroughly, and document.
De-virtualize brw_blorp_params class
i965/blorp: Convert brw_blorp_mip_info into a C struct
i965/blorp: Convert brw_blorp_surface_info into a C struct
i965/blorp: Convert brw_blorp_coord_transform_params into a C struct
i965/blorp: Convert brw_blorp_wm_push_constants into a C struct
i965/blorp: Convert more stuff to C
Convert more stuff to C
Convert brw_blorp_params into C
Convert more stuff to C
Convert brw_hiz_op_params to C
Convert brw_blorp_blit_params to C
Convert the rest of brw_blorp.h to C
!UPSTREAM: i965/blorp: Merge into brw_wm_prog.

TODO: disentangle prep work.
i965/blorp: Use gen7_push_constant_alloc
Convert to C: clean up init