ssl: reorganize guards surrounding ssl_get_ecdh_params_from_cert()

Signed-off-by: Valerio Setti <valerio.setti@nordicsemi.no>
diff --git a/library/ssl_tls12_server.c b/library/ssl_tls12_server.c
index b4719d6..4433e8b 100644
--- a/library/ssl_tls12_server.c
+++ b/library/ssl_tls12_server.c
@@ -2604,9 +2604,9 @@
 }
 #endif /* MBEDTLS_KEY_EXCHANGE_CERT_REQ_ALLOWED_ENABLED */
 
-#if defined(MBEDTLS_USE_PSA_CRYPTO) &&                      \
-    (defined(MBEDTLS_KEY_EXCHANGE_ECDH_RSA_ENABLED) || \
+#if (defined(MBEDTLS_KEY_EXCHANGE_ECDH_RSA_ENABLED) || \
     defined(MBEDTLS_KEY_EXCHANGE_ECDH_ECDSA_ENABLED))
+#if defined(MBEDTLS_USE_PSA_CRYPTO)
 MBEDTLS_CHECK_RETURN_CRITICAL
 static int ssl_get_ecdh_params_from_cert(mbedtls_ssl_context *ssl)
 {
@@ -2716,8 +2716,7 @@
 
     return ret;
 }
-#elif defined(MBEDTLS_KEY_EXCHANGE_ECDH_RSA_ENABLED) || \
-    defined(MBEDTLS_KEY_EXCHANGE_ECDH_ECDSA_ENABLED)
+#else /* MBEDTLS_USE_PSA_CRYPTO */
 MBEDTLS_CHECK_RETURN_CRITICAL
 static int ssl_get_ecdh_params_from_cert(mbedtls_ssl_context *ssl)
 {
@@ -2743,6 +2742,7 @@
 
     return 0;
 }
+#endif /* MBEDTLS_USE_PSA_CRYPTO */
 #endif /* MBEDTLS_KEY_EXCHANGE_ECDH_RSA_ENABLED) ||
           MBEDTLS_KEY_EXCHANGE_ECDH_ECDSA_ENABLED */