s390/mm: make pte_free_tlb() similar to pXd_free_tlb()

Make pte_free_tlb() look similar to pXd_free_tlb() family
functions.

Reviewed-by: Heiko Carstens <hca@linux.ibm.com>
Reviewed-by: Gerald Schaefer <gerald.schaefer@linux.ibm.com>
Signed-off-by: Alexander Gordeev <agordeev@linux.ibm.com>
Signed-off-by: Vasily Gorbik <gor@linux.ibm.com>