crypto: caam - check zero-length input

Check zero-length input, for skcipher algorithm, to solve the extra
tests. This is a valid operation, therefore the API will return no error.

Signed-off-by: Iuliana Prodan <[e-mail]>
Reviewed-by: Horia Geanta <[e-mail]>
Signed-off-by: Herbert Xu <[e-mail]>

drivers/crypto/caam/caamalg.c

···
 	u32 *desc;
 	int ret = 0;
 
+	if (!req->cryptlen)
+		return 0;
+
 	/* allocate extended descriptor */
 	edesc = skcipher_edesc_alloc(req, DESC_JOB_IO_LEN * CAAM_CMD_SZ);
 	if (IS_ERR(edesc))
···
 	struct device *jrdev = ctx->jrdev;
 	u32 *desc;
 	int ret = 0;
+
+	if (!req->cryptlen)
+		return 0;
 
 	/* allocate extended descriptor */
 	edesc = skcipher_edesc_alloc(req, DESC_JOB_IO_LEN * CAAM_CMD_SZ);

drivers/crypto/caam/caamalg_qi.c

···
 	struct caam_ctx *ctx = crypto_skcipher_ctx(skcipher);
 	int ret;
 
+	if (!req->cryptlen)
+		return 0;
+
 	if (unlikely(caam_congested))
 		return -EAGAIN;
 

drivers/crypto/caam/caamalg_qi2.c

···
 	struct caam_request *caam_req = skcipher_request_ctx(req);
 	int ret;
 
+	if (!req->cryptlen)
+		return 0;
+
 	/* allocate extended descriptor */
 	edesc = skcipher_edesc_alloc(req);
 	if (IS_ERR(edesc))
···
 	struct caam_request *caam_req = skcipher_request_ctx(req);
 	int ret;
 
+	if (!req->cryptlen)
+		return 0;
 	/* allocate extended descriptor */
 	edesc = skcipher_edesc_alloc(req);
 	if (IS_ERR(edesc))