crypto: lib/sha256 - Remove redundant and unused sha224_update

The function sha224_update is exactly the same as sha256_update.
Moreover it's not even used in the kernel so it can be removed.
Signed-off-by: Herbert Xu <herbert@gondor.apana.org.au>

include/crypto/sha2.h

@@ -128,7 +128,7 @@ static inline void sha224_init(struct sha256_state *sctx)
 	sctx->state[7] = SHA224_H7;
 	sctx->count = 0;
 }
-void sha224_update(struct sha256_state *sctx, const u8 *data, unsigned int len);
+/* Simply use sha256_update as it is equivalent to sha224_update. */
 void sha224_final(struct sha256_state *sctx, u8 *out);
 
 #endif /* _CRYPTO_SHA2_H */

lib/crypto/sha256.c

@@ -151,12 +151,6 @@ void sha256_update(struct sha256_state *sctx, const u8 *data, unsigned int len)
 }
 EXPORT_SYMBOL(sha256_update);
 
-void sha224_update(struct sha256_state *sctx, const u8 *data, unsigned int len)
-{
-	sha256_update(sctx, data, len);
-}
-EXPORT_SYMBOL(sha224_update);
-
 static void __sha256_final(struct sha256_state *sctx, u8 *out, int digest_words)
 {
 	__be32 *dst = (__be32 *)out;