crypto: query gcrypt for cipher availability

crypto: query gcrypt for cipher availability

Just because a cipher is defined in the gcrypt header file, does not
imply that it can be used. Distros can filter the list of ciphers when
building gcrypt. For example, RHEL-9 disables the SM4 cipher. It is
also possible that running in FIPS mode might dynamically change what
ciphers are available at runtime.

qcrypto_cipher_supports must therefore query gcrypt directly to check
for cipher availability.

Reviewed-by: Philippe Mathieu-Daudé <philmd@linaro.org>
Reviewed-by: Thomas Huth <thuth@redhat.com>
Signed-off-by: Daniel P. Berrangé <berrange@redhat.com>