stmhal: Fix machine.unique_id() function to work for all MCUs.

stmhal/modmachine.c

@@ -115,7 +115,7 @@ MP_DEFINE_CONST_FUN_OBJ_VAR_BETWEEN(machine_info_obj, 0, 1, machine_info);
 
 // Returns a string of 12 bytes (96 bits), which is the unique ID for the MCU.
 STATIC mp_obj_t machine_unique_id(void) {
-    byte *id = (byte*)0x1fff7a10;
+    byte *id = (byte*)MP_HAL_UNIQUE_ID_ADDRESS;
     return mp_obj_new_bytes(id, 12);
 }
 MP_DEFINE_CONST_FUN_OBJ_0(machine_unique_id_obj, machine_unique_id);