gallium: split transfer_inline_write into buffer and texture callbacks

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>

src/gallium/docs/source/context.rst

@@ -538,8 +538,9 @@ to the transfer object remains unchanged (i.e. it can be non-NULL).
 the transfer object. The pointer into the resource should be considered
 invalid and discarded.
 
-``transfer_inline_write`` performs a simplified transfer for simple writes.
-Basically transfer_map, data write, and transfer_unmap all in one.
+``texture_subdata`` and ``buffer_subdata`` perform a simplified
+transfer for simple writes. Basically transfer_map, data write, and
+transfer_unmap all in one.
 
 
 The box parameter to some of these functions defines a 1D, 2D or 3D