[lib/LTO] Simplify logic removing set but unused variable. NFCI.

Reported by David Binderman and ack'ed by Teresa on IRC.
PR: 31527

git-svn-id: https://llvm.org/svn/llvm-project/llvm/trunk@291000 91177308-0d34-0410-b5e6-96231b3b80d8
1 file changed