gallium: add pipe surface layout value (Roland Scheidegger)

src/gallium/include/pipe/p_defines.h

@@ -173,6 +173,12 @@ enum pipe_texture_target {
 #define PIPE_SURFACE        2  /**< user-created surfaces */
 
 
+/**
+ * Surface layout
+ */
+#define PIPE_SURFACE_LAYOUT_LINEAR  0
+
+
 /**
  * Surface status
  */

src/gallium/include/pipe/p_state.h

@@ -271,6 +271,7 @@ struct pipe_surface
    unsigned width;
    unsigned height;
    unsigned pitch;               /**< in pixels */
+   unsigned layout;              /**< PIPE_SURFACE_LAYOUT_x */
    unsigned offset;              /**< offset from start of buffer, in bytes */
    unsigned refcount;
    unsigned usage;              /**< PIPE_BUFFER_USAGE_*  */