engine: Fix compile error on Fedora 40

ibmca_pkey.c:627:47: error: passing argument 2 of 'EVP_PKEY_meth_set_copy'
from incompatible pointer type [-Wincompatible-pointer-types]
      627 |     EVP_PKEY_meth_set_copy(ibmca_ed448_pmeth, ibmca_ed448_copy);

Signed-off-by: Ingo Franzki <ifranzki@linux.ibm.com>

Author: ifranzki

src/engine/ibmca_pkey.c

@@ -258,7 +258,7 @@ static int ibmca_x448_derive(EVP_PKEY_CTX *pkey_ctx, unsigned char *key, size_t
 
 /* ED25519 */
 
-static int ibmca_ed25519_copy(EVP_PKEY_CTX *to, EVP_PKEY_CTX *from)
+static int ibmca_ed25519_copy(EVP_PKEY_CTX *to, const EVP_PKEY_CTX *from)
 {
     return 1;
 }
@@ -402,7 +402,7 @@ static int ibmca_ed25519_verify(EVP_MD_CTX *md_ctx, const unsigned char *sig,
 
 /* ED448 */
 
-static int ibmca_ed448_copy(EVP_PKEY_CTX *to, EVP_PKEY_CTX *from)
+static int ibmca_ed448_copy(EVP_PKEY_CTX *to, const EVP_PKEY_CTX *from)
 {
     return 1;
 }