mm: page-flags.h: Typo fix (It -> If)

The "If" was wrongly spelled as "It".

Link: https://lkml.kernel.org/r/1608959036-91409-1-git-send-email-guoren@kernel.orgSigned-off-by: NGuo Ren <guoren@linux.alibaba.com>
Cc: Oscar Salvador <osalvador@suse.de>
Cc: Alexander Duyck <alexander.h.duyck@linux.intel.com>
Cc: David Hildenbrand <david@redhat.com>
Cc: Steven Price <steven.price@arm.com>
Signed-off-by: NAndrew Morton <akpm@linux-foundation.org>
Signed-off-by: NLinus Torvalds <torvalds@linux-foundation.org>

include/linux/page-flags.h

@@ -810,7 +810,7 @@ static inline void ClearPageSlabPfmemalloc(struct page *page)
 
 /*
  * Flags checked when a page is freed.  Pages being freed should not have
- * these flags set.  It they are, there is a problem.
+ * these flags set.  If they are, there is a problem.
  */
 #define PAGE_FLAGS_CHECK_AT_FREE				\
 	(1UL << PG_lru		| 1UL << PG_locked	|	\
@@ -821,7 +821,7 @@ static inline void ClearPageSlabPfmemalloc(struct page *page)
 
 /*
  * Flags checked when a page is prepped for return by the page allocator.
- * Pages being prepped should not have these flags set.  It they are set,
+ * Pages being prepped should not have these flags set.  If they are set,
  * there has been a kernel bug or struct page corruption.
  *
  * __PG_HWPOISON is exceptional because it needs to be kept beyond page's