Fix sign-compare warning

system/bpf/bpfloader/BpfLoader.cpp:79:23: error: comparison of integers of different signs: 'int' and 'std::__1::vector<android::bpf::BpfMapInfo, std::__1::allocator<android::bpf::BpfMapInfo> >::size_type' (aka 'unsigned long') [-Werror,-Wsign-compare]
    for (int i = 0; i < mapPatterns.size(); i++) {
                    ~ ^ ~~~~~~~~~~~~~~~~~~`

Test: m checkbuild
Change-Id: If2891bfc7655aea34499975763f72e0a25b32289
1 file changed