platform/x86: intel_cht_int33fe: Accept errors of i2c_acpi_new_device()

In the future i2c_acpi_new_device() will return error pointer in some cases.
Prepare intel_cht_int33fe driver to support that.

Signed-off-by: Andy Shevchenko <andriy.shevchenko@linux.intel.com>
Reviewed-by: Heikki Krogerus <heikki.krogerus@linux.intel.com>
Reviewed-by: Hans de Goede <hdegoede@redhat.com>