vbo: remove redundant code in vbo_exec_fixup_vertex

Callers of this function also set FLUSH_STORED_VERTICES for attr == 0.

Reviewed-by: Mathias Fröhlich <mathias.froehlich@web.de>
Part-of: <https://gitlab.freedesktop.org/mesa/mesa/merge_requests/3861>

src/mesa/vbo/vbo_exec_api.c

@@ -427,13 +427,6 @@ vbo_exec_fixup_vertex(struct gl_context *ctx, GLuint attr,
 
    exec->vtx.attr[attr].active_size = newSize;
    exec->vtx.attr[attr].type = newType;
-
-   /* Does setting NeedFlush belong here?  Necessitates resetting
-    * vtxfmt on each flush (otherwise flags won't get reset
-    * afterwards).
-    */
-   if (attr == 0)
-      ctx->Driver.NeedFlush |= FLUSH_STORED_VERTICES;
 }