Use clog from cpuinfo/deps instead of downloading (#33947)
Summary:
Pull Request resolved: https://github.com/pytorch/pytorch/pull/33947
XNNPACK was downloading clog because we weren't setting CLOG_SOURCE_DIR.
Actually, it was downloading cpuinfo and pointing to the copy of clog
within that. So let's just point to the copy of clog within the cpuinfo
submodule we already have.
(Note: this ignores all push blocking failures!)
Test Plan:
Ran cmake and didn't see any downloading.
Verified that our clog is the same as the one that was being downloaded
with `diff -Naur`.
Differential Revision: D20169656
Pulled By: suo
fbshipit-source-id: ba0f7d1535f702e504fbc4f0102e567f860db94b
