Address the following complier warning:

   arch/x86/kernel/apic/io_apic.c:2543: warning: `eoi_ioapic_irq' defined but not used

By moving that function (and eoi_ioapic_irq()) into an existing
#ifdef CONFIG_INTR_REMAP section of the code.

[ Impact: cleanup ]
Signed-off-by: Suresh Siddha <suresh.b.siddha@intel.com>
Cc: dwmw2@infradead.org
Cc: Weidong Han <weidong.han@intel.com>
LKML-Reference: <20090420200450.271099000@linux-os.sc.intel.com>
Signed-off-by: Ingo Molnar <mingo@elte.hu>
Cc: Weidong Han <weidong.han@intel.com>