x86, ioapic: Pass struct irq_attr * to setup_ioapic_irq()

Do not expand that struct, and just pass pointer to reduce the
number of parameters in related functions.

Signed-off-by: Yinghai Lu <yinghai@kernel.org>
Cc: Naga Chumbalkar <nagananda.chumbalkar@hp.com>
Cc: Suresh Siddha <suresh.b.siddha@intel.com>
Link: http://lkml.kernel.org/r/4E9542B1.7050800@oracle.com


Signed-off-by: Ingo Molnar <mingo@elte.hu>