gallium/radeon: remove radeon_winsys_cs_handle

"radeon_winsys_cs_handle *cs_buf" is now equivalent to "pb_buffer *buf".

Reviewed-by: Nicolai Hähnle <nicolai.haehnle@amd.com>
Reviewed-by: Edward O'Callaghan <eocallaghan@alterapraxis.com>
Reviewed-by: Michel Dänzer <michel.daenzer@amd.com>

src/gallium/drivers/r600/r600_asm.c

@@ -2633,7 +2633,7 @@ void *r600_create_vertex_fetch_shader(struct pipe_context *ctx,
 	} else {
 		memcpy(bytecode, bc.bytecode, fs_size);
 	}
-	rctx->b.ws->buffer_unmap(shader->buffer->cs_buf);
+	rctx->b.ws->buffer_unmap(shader->buffer->buf);
 
 	r600_bytecode_clear(&bc);
 	return shader;