i2c: designware: Propagate firmware node

Propagate firmware node by using a specific API call, i.e. device_set_node().

Reviewed-by: Andi Shyti <andi.shyti@kernel.org>
Signed-off-by: Andy Shevchenko <andriy.shevchenko@linux.intel.com>
Acked-by: Jarkko Nikula <jarkko.nikula@linux.intel.com>
Tested-by: Serge Semin <fancer.lancer@gmail.com>
Signed-off-by: Andi Shyti <andi.shyti@kernel.org>