Documentation/sysctl/vm.txt: update __vm_enough_memory()'s path

__vm_enough_memory has moved to mm/util.c.

Link: http://lkml.kernel.org/r/E18EDF4A4FA4A04BBFA824B6D7699E532A7E5913@EXMBX-SZMAIL013.tencent.comSigned-off-by: Juvi Liu <juviliu@tencent.com>
Reviewed-by: Andrew Morton <akpm@linux-foundation.org>
Signed-off-by: Andrew Morton <akpm@linux-foundation.org>
Signed-off-by: Linus Torvalds <torvalds@linux-foundation.org>

Documentation/sysctl/vm.txt

@@ -691,7 +691,7 @@ and don't use much of it.
 The default value is 0.
 
 See Documentation/vm/overcommit-accounting.rst and
-mm/mmap.c::__vm_enough_memory() for more information.
+mm/util.c::__vm_enough_memory() for more information.
 
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