platform/x86: i2c-multi-instantiate: Defer probe when no adapter found

Likewise the rest of the i2c_acpi_new_device() users, defer the probe
of the i2c-multi-intantiate driver in case adapter is not yet found.

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>