MachineModuleInfo: Prefer the LLVM_NODISCARD spelling

Update a function annotated with LLVM_ATTRIBUTE_UNUSED_RESULT to use
LLVM_NODISCARD instead.

git-svn-id: https://llvm.org/svn/llvm-project/llvm/trunk@284346 91177308-0d34-0410-b5e6-96231b3b80d8
1 file changed