s390/tlb: Use mm_has_pgste() instead of mm_alloc_pgste()

An mm has pgstes only after s390_enable_sie() has been called, while
mm_alloc_pgste() may be always true (e.g. via sysctl setting).

Limit the calls to gmap_unlink() in pte_free_tlb() to those cases
where there might be something to unlink.

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

Author: hcahca

arch/s390/include/asm/tlb.h

@@ -84,7 +84,7 @@ static inline void pte_free_tlb(struct mmu_gather *tlb, pgtable_t pte,
 	tlb->mm->context.flush_mm = 1;
 	tlb->freed_tables = 1;
 	tlb->cleared_pmds = 1;
-	if (mm_alloc_pgste(tlb->mm))
+	if (mm_has_pgste(tlb->mm))
 		gmap_unlink(tlb->mm, (unsigned long *)pte, address);
 	tlb_remove_ptdesc(tlb, virt_to_ptdesc(pte));
 }