r600: enable GL_ARB_pixel_buffer_object

src/mesa/drivers/dri/r600/r600_context.c

@@ -140,6 +140,7 @@ static const struct dri_extension card_extensions[] = {
   {"GL_NV_blend_square",		NULL},
   {"GL_NV_vertex_program",		GL_NV_vertex_program_functions},
   {"GL_SGIS_generate_mipmap",		NULL},
+  {"GL_ARB_pixel_buffer_object",        NULL},
   {NULL,				NULL}
   /* *INDENT-ON* */
 };