mm: fix a spelling mistake

Signed-off-by Wei Yuan <weiyuan.wei@huawei.com>
Acked-by: NRik van Riel <riel@redhat.com>
Signed-off-by: NAndrew Morton <akpm@linux-foundation.org>
Signed-off-by: NLinus Torvalds <torvalds@linux-foundation.org>

mm/page_alloc.c

@@ -1739,7 +1739,7 @@ static bool __zone_watermark_ok(struct zone *z, unsigned int order,
 			unsigned long mark, int classzone_idx, int alloc_flags,
 			long free_pages)
 {
-	/* free_pages my go negative - that's OK */
+	/* free_pages may go negative - that's OK */
 	long min = mark;
 	int o;
 	long free_cma = 0;