The ACPI subsys is going to move over to instantiating ACPI enumerated
HCIs as serdevs, rather then as platform devices.

So we need to make bcm_acpi_probe() suitable for use on non platform-
devices too, which means that we cannot rely on platform_get_irq()
getting called.

This commit modifies bcm_acpi_probe() to directly get the irq from
the ACPI resources, this is a preparation patch for adding (runtime)pm
support to the serdev path.
Signed-off-by: NHans de Goede <hdegoede@redhat.com>
Signed-off-by: NMarcel Holtmann <marcel@holtmann.org>