Adapt to the new key allocation mechanism

diff --git a/programs/ssl/ssl_client2.c b/programs/ssl/ssl_client2.c
index a98a3a2..a8c16dc 100644
--- a/programs/ssl/ssl_client2.c
+++ b/programs/ssl/ssl_client2.c
@@ -571,7 +571,7 @@
     const char *pers = "ssl_client2";
 
 #if defined(MBEDTLS_USE_PSA_CRYPTO)
-    psa_key_slot_t slot = 0;
+    psa_key_handle_t slot = 0;
     psa_algorithm_t alg = 0;
     psa_key_policy_t policy;
     psa_status_t status;
@@ -594,7 +594,7 @@
     mbedtls_x509_crt clicert;
     mbedtls_pk_context pkey;
 #if defined(MBEDTLS_USE_PSA_CRYPTO)
-    psa_key_slot_t key_slot = 0; /* invalid key slot */
+    psa_key_handle_t key_slot = 0; /* invalid key slot */
 #endif
 #endif
     char *p, *q;
@@ -1594,7 +1594,7 @@
     if( opt.psk_opaque != 0 )
     {
         /* The algorithm has already been determined earlier. */
-        status = mbedtls_psa_get_free_key_slot( &slot );
+        status = psa_allocate_key( PSA_KEY_TYPE_DERIVE, psk_len * 8, &slot );
         if( status != PSA_SUCCESS )
         {
             ret = MBEDTLS_ERR_SSL_HW_ACCEL_FAILED;