Add missing dependencies on MBEDTLS_KEY_EXCHANGE_SOME_PSK_ENABLED

Fix dependencies across test ssl programs.
Signed-off-by: Andrzej Kurek <andrzej.kurek@arm.com>
diff --git a/programs/ssl/ssl_client2.c b/programs/ssl/ssl_client2.c
index 8e62dbe..1dfe772 100644
--- a/programs/ssl/ssl_client2.c
+++ b/programs/ssl/ssl_client2.c
@@ -681,9 +681,11 @@
     const char *pers = "ssl_client2";
 
 #if defined(MBEDTLS_USE_PSA_CRYPTO)
+#if defined(MBEDTLS_KEY_EXCHANGE_SOME_PSK_ENABLED)
     psa_key_id_t slot = 0;
     psa_algorithm_t alg = 0;
     psa_key_attributes_t key_attributes;
+#endif
     psa_status_t status;
 #endif
 
@@ -1415,6 +1417,7 @@
         }
 
 #if defined(MBEDTLS_USE_PSA_CRYPTO)
+#if defined (MBEDTLS_KEY_EXCHANGE_SOME_PSK_ENABLED)
         if( opt.psk_opaque != 0 )
         {
             /* Ensure that the chosen ciphersuite is PSK-only; we must know
@@ -1436,6 +1439,7 @@
 #endif /* MBEDTLS_SHA512_C */
                 alg = PSA_ALG_TLS12_PSK_TO_MS(PSA_ALG_SHA_256);
         }
+#endif /* MBEDTLS_KEY_EXCHANGE_SOME_PSK_ENABLED */
 #endif /* MBEDTLS_USE_PSA_CRYPTO */
     }