For APIC case of interrupt we don't fail a ->probe() of the driver,
which makes kernel to print a lot of warnings from the children.

We have two options here:
- switch to platform_get_irq_optional(), though it won't stop children
  to be probed and failed
- fail the ->probe() of i2c-multi-instantiate

Since the in reality we never had devices in the wild where IRQ resource
is optional, the latter solution suits the best.

Fixes: 799d3379 ("platform/x86: i2c-multi-instantiate: Introduce IOAPIC IRQ support")
Reported-by: Ammy Yi <ammy.yi@intel.com>
Cc: Heikki Krogerus <heikki.krogerus@linux.intel.com>
Cc: Hans de Goede <hdegoede@redhat.com>
Signed-off-by: Andy Shevchenko <andriy.shevchenko@linux.intel.com>
Reviewed-by: Heikki Krogerus <heikki.krogerus@linux.intel.com>