x86, acpi/irq: Fix acpi_sci_ioapic_setup so it has both bus_irq and gsi

Currently acpi_sci_ioapic_setup calls mp_override_legacy_irq with
bus_irq == gsi, which is wrong if we are comming from an override
Instead pass the bus_irq into acpi_sci_ioapic_setup.

This fix was inspired by a similar fix from:
Yinghai Lu <yinghai@kernel.org>

Signed-off-by: Eric W. Biederman <ebiederm@xmission.com>
LKML-Reference: <1269936436-7039-4-git-send-email-ebiederm@xmission.com>
Signed-off-by: H. Peter Anvin <hpa@zytor.com>