[CMake] Use if(... IN_LIST ...) instead of list(FIND...)

NFC. This is just a little code cleanup to make things easier to read and understand.

git-svn-id: https://llvm.org/svn/llvm-project/llvm/trunk@282510 91177308-0d34-0410-b5e6-96231b3b80d8
1 file changed