Framebuffer: Drop bitmap save callback entry; core doesn't use it.

frontends/framebuffer/bitmap.c

@@ -132,20 +132,6 @@ static void bitmap_destroy(void *bitmap)
 }
 
 
-/**
- * Save a bitmap in the platform's native format.
- *
- * \param  bitmap  a bitmap, as returned by bitmap_create()
- * \param  path    pathname for file
- * \param flags flags controlling how the bitmap is saved.
- * \return true on success, false on error and error reported
- */
-static bool bitmap_save(void *bitmap, const char *path, unsigned flags)
-{
-	return true;
-}
-
-
 /**
  * The bitmap image has changed, so flush any persistant cache.
  *
@@ -331,7 +317,6 @@ static struct gui_bitmap_table bitmap_table = {
 	.get_rowstride = bitmap_get_rowstride,
 	.get_width = bitmap_get_width,
 	.get_height = bitmap_get_height,
-	.save = bitmap_save,
 	.modified = bitmap_modified,
 	.render = bitmap_render,
 };