selftests/sgx: Ignore OpenSSL 3.0 deprecated functions warning

OpenSSL 3.0 deprecates some of the functions used in the SGX
selftests, causing build errors on new distros. For now ignore
the warnings until support for the functions is no longer
available and mark FIXME so that it can be clear this should
be removed at some point.

Signed-off-by: Kristen Carlson Accardi <kristen@linux.intel.com>
Reviewed-by: Jarkko Sakkinen <jarkko@kernel.org>
Signed-off-by: Shuah Khan <skhan@linuxfoundation.org>