crypto: skcipher - remove crypto_skcipher::keysize

Due to the removal of the blkcipher and ablkcipher algorithm types,
crypto_skcipher::keysize is now redundant since it always equals
crypto_skcipher_alg(tfm)->max_keysize.

Remove it and update crypto_skcipher_default_keysize() accordingly.

Also rename crypto_skcipher_default_keysize() to
crypto_skcipher_max_keysize() to clarify that it specifically returns
the maximum key size, not some unspecified "default".

Signed-off-by: Eric Biggers <ebiggers@google.com>
Signed-off-by: Herbert Xu <herbert@gondor.apana.org.au>
diff --git a/crypto/skcipher.c b/crypto/skcipher.c
index 7d2e722..6cfafd8 100644
--- a/crypto/skcipher.c
+++ b/crypto/skcipher.c
@@ -585,7 +585,7 @@ static unsigned int crypto_skcipher_extsize(struct crypto_alg *alg)
 
 static void skcipher_set_needkey(struct crypto_skcipher *tfm)
 {
-	if (tfm->keysize)
+	if (crypto_skcipher_max_keysize(tfm) != 0)
 		crypto_skcipher_set_flags(tfm, CRYPTO_TFM_NEED_KEY);
 }
 
@@ -686,7 +686,6 @@ static int crypto_skcipher_init_tfm(struct crypto_tfm *tfm)
 	skcipher->setkey = skcipher_setkey;
 	skcipher->encrypt = alg->encrypt;
 	skcipher->decrypt = alg->decrypt;
-	skcipher->keysize = alg->max_keysize;
 
 	skcipher_set_needkey(skcipher);