crypto: sha256_ssse3 - use correct module alias for sha224

Commit a710f761f (crypto: sha256_ssse3 - add sha224 support) attempted to add
MODULE_ALIAS for SHA-224, but it ended up being "sha384", probably because
mix-up with previous commit 340991e30 (crypto: sha512_ssse3 - add sha384
support). Patch corrects module alias to "sha224".

Reported-by: Pierre-Mayeul Badaire <pierre-mayeul.badaire@m4x.org>
Signed-off-by: Jussi Kivilinna <jussi.kivilinna@iki.fi>
Signed-off-by: Herbert Xu <herbert@gondor.apana.org.au>