The definition of crypto_lookup_skcipher() was already removed in
commit 3a01d0ee ("crypto: skcipher - Remove top-level givcipher
interface").  So the declaration should be removed too.
Signed-off-by: NEric Biggers <ebiggers@google.com>
Signed-off-by: NHerbert Xu <herbert@gondor.apana.org.au>