Remove duplicate option from documentation.

git-svn-id: https://llvm.org/svn/llvm-project/llvm/trunk@320258 91177308-0d34-0410-b5e6-96231b3b80d8
(cherry picked from commit 012e6e52d467e9a0a99bf41d8cc760153d967d9d)
1 file changed