cert host tools: Stop complaining about deprecated OpenSSL functions

OpenSSL 3.0 deprecated the OpenSSL's ENGINE API.  That is as may be, but
the kernel build host tools still use it.  Disable the warning about
deprecated declarations until somebody who cares fixes it.

Signed-off-by: Linus Torvalds <torvalds@linux-foundation.org>
Change-Id: I655a75665920983abc9c3b0d73abfcb34f41b610