to reduce the call indirections with u_resource_vtbl.

The worst call tree you could get was:
  - u_transfer_inline_write_vtbl
    - u_default_transfer_inline_write
      - u_transfer_map_vtbl
        - driver_transfer_map
      - u_transfer_unmap_vtbl
        - driver_transfer_unmap

That's 6 indirect calls. Some drivers only had 5. The goal is to have
1 indirect call for drivers that care. The resource type can be determined
statically at most call sites.

The new interface is:
  pipe_context::buffer_subdata(ctx, resource, usage, offset, size, data)
  pipe_context::texture_subdata(ctx, resource, level, usage, box, data,
                                stride, layer_stride)

v2: fix whitespace, correct ilo's behavior

Reviewed-by: Nicolai Hähnle <nicolai.haehnle@amd.com>
Acked-by: Roland Scheidegger <sroland@vmware.com>