crypto: hisilicon/hpre - fix memory leak in hpre_curve25519_src_init()

hpre_curve25519_src_init() allocates memory for 'ptr' before calling
memcmp(). If memcmp() returns 0, the function will return '-EINVAL'
without freeing memory.
Signed-off-by: Weili Qian <qianweili@huawei.com>
Signed-off-by: Herbert Xu <herbert@gondor.apana.org.au>

drivers/crypto/hisilicon/hpre/hpre_crypto.c

@@ -1862,7 +1862,7 @@ static int hpre_curve25519_src_init(struct hpre_asym_request *hpre_req,
 	 */
 	if (memcmp(ptr, p, ctx->key_sz) == 0) {
 		dev_err(dev, "gx is p!\n");
-		return -EINVAL;
+		goto err;
 	} else if (memcmp(ptr, p, ctx->key_sz) > 0) {
 		hpre_curve25519_src_modulo_p(ptr);
 	}