x86 early quirks: eliminate unused function

Impact: cleanup

this warning:

  arch/x86/kernel/early-quirks.c:99: warning: ‘ati_ixp4x0_rev’ defined but not used

triggers because ati_ixp4x0_rev() is only used in the
ACPI && X86_IO_APIC case.

Signed-off-by: Ingo Molnar <mingo@elte.hu>
diff --git a/arch/x86/kernel/early-quirks.c b/arch/x86/kernel/early-quirks.c
index 76b8cd9..ebdb85c 100644
--- a/arch/x86/kernel/early-quirks.c
+++ b/arch/x86/kernel/early-quirks.c
@@ -97,6 +97,7 @@
 }
 
 #if defined(CONFIG_ACPI) && defined(CONFIG_X86_IO_APIC)
+#if defined(CONFIG_ACPI) && defined(CONFIG_X86_IO_APIC)
 static u32 __init ati_ixp4x0_rev(int num, int slot, int func)
 {
 	u32 d;
@@ -114,6 +115,7 @@
 	d &= 0xff;
 	return d;
 }
+#endif
 
 static void __init ati_bugs(int num, int slot, int func)
 {