Work around bpf verifier limit

New clang-r437112 generates optimized code that
older bpf verifier cannot tell if the returned
value is always 1 or 0.

Test: TH boot test on wembley
Bug: 204131517
Bug: 201432564
Change-Id: I463ab177667a26088b8eecb5b8b7d85057980866
1 file changed