crypto: sun8i-ss - fix memdup.cocci warnings

Use kmemdup rather than duplicating its implementation

Generated by: scripts/coccinelle/api/memdup.cocci

Fixes: f08fcced ("crypto: allwinner - Add sun8i-ss cryptographic offloader")
CC: Corentin Labbe <clabbe.montjoie@gmail.com>
Signed-off-by: kbuild test robot <lkp@intel.com>
Signed-off-by: Julia Lawall <julia.lawall@lip6.fr>
Signed-off-by: Herbert Xu <herbert@gondor.apana.org.au>

drivers/crypto/allwinner/sun8i-ss/sun8i-ss-cipher.c

@@ -398,10 +398,9 @@ int sun8i_ss_aes_setkey(struct crypto_skcipher *tfm, const u8 *key,
 		kfree(op->key);
 	}
 	op->keylen = keylen;
-	op->key = kmalloc(keylen, GFP_KERNEL | GFP_DMA);
+	op->key = kmemdup(key, keylen, GFP_KERNEL | GFP_DMA);
 	if (!op->key)
 		return -ENOMEM;
-	memcpy(op->key, key, keylen);
 
 	crypto_sync_skcipher_clear_flags(op->fallback_tfm, CRYPTO_TFM_REQ_MASK);
 	crypto_sync_skcipher_set_flags(op->fallback_tfm, tfm->base.crt_flags & CRYPTO_TFM_REQ_MASK);
@@ -426,10 +425,9 @@ int sun8i_ss_des3_setkey(struct crypto_skcipher *tfm, const u8 *key,
 		kfree(op->key);
 	}
 	op->keylen = keylen;
-	op->key = kmalloc(keylen, GFP_KERNEL | GFP_DMA);
+	op->key = kmemdup(key, keylen, GFP_KERNEL | GFP_DMA);
 	if (!op->key)
 		return -ENOMEM;
-	memcpy(op->key, key, keylen);
 
 	crypto_sync_skcipher_clear_flags(op->fallback_tfm, CRYPTO_TFM_REQ_MASK);
 	crypto_sync_skcipher_set_flags(op->fallback_tfm, tfm->base.crt_flags & CRYPTO_TFM_REQ_MASK);