[Kernel-janitors] Documentation/sysctl/vm.txt outdated reference

Lines 55 & 56 of Documentation/sysctl/vm.txt:

See Documentation/vm/overcommit-accounting and
mm/mmap.c::vm_enough_memory() for more information.

There is no vm_enough_memory() in mm/mmap.c, the function must have been 
moved to a new location, and the documentation has not been updated yet.