iris: disable aux on first get_param if not created with aux

This moves the fix from commit 361f3d19 to happen in get_param
(used now instead of get_handle by st/dri). This fixes artifacts
seen with Xorg and CCS_E.

Fixes: fc12fd05 "iris: Implement pipe_screen::resource_get_param"
Signed-off-by: Tapani Pälli <tapani.palli@intel.com>
Reviewed-by: Kenneth Graunke <kenneth@whitecape.org>
(cherry picked from commit f4d91692)