sparc: fix handling of page table constructor failure

The page has just been allocated, so its refcount is 1.  free_unref_page()
is for use on pages which have a zero refcount.  Use __free_page() like
the other implementations of pte_alloc_one().

Link: https://lkml.kernel.org/r/20201125034655.27687-1-willy@infradead.org
Fixes: 1ae9ae5f ("sparc: handle pgtable_page_ctor() fail")
Signed-off-by: Matthew Wilcox (Oracle) <willy@infradead.org>
Reviewed-by: David Hildenbrand <david@redhat.com>
Reviewed-by: Mike Rapoport <rppt@linux.ibm.com>
Acked-by: Vlastimil Babka <vbabka@suse.cz>
Cc: David Miller <davem@davemloft.net>
Signed-off-by: Andrew Morton <akpm@linux-foundation.org>
Signed-off-by: Linus Torvalds <torvalds@linux-foundation.org>

arch/sparc/mm/init_64.c

@@ -2894,7 +2894,7 @@ pgtable_t pte_alloc_one(struct mm_struct *mm)
 	if (!page)
 		return NULL;
 	if (!pgtable_pte_page_ctor(page)) {
-		free_unref_page(page);
+		__free_page(page);
 		return NULL;
 	}
 	return (pte_t *) page_address(page);