[ACPI] PNPACPI vs sound IRQ

http://bugme.osdl.org/show_bug.cgi?id=4016

Written-by: David Shaohua Li <shaohua.li@intel.com>
Acked-by: Adam Belay <abelay@novell.com>
Signed-off-by: Len Brown <len.brown@intel.com>