x86: uniq_ioapic_id - fix section mismatch warning

Fix folowing warning:
WARNING: arch/x86/kernel/built-in.o(.text+0x10799): Section mismatch in reference from the function uniq_ioapic_id()

uniq_ioapic_id() is only used by __init mp_register_ioapic(). Annotate uniq_ioapic_id() with __init.
Signed-off-by: Jacek Luczak <luczak.jacek@gmail.com>
Signed-off-by: Ingo Molnar <mingo@elte.hu>
Signed-off-by: Thomas Gleixner <tglx@linutronix.de>

arch/x86/kernel/mpparse.c

@@ -817,7 +817,7 @@ static int mp_find_ioapic(int gsi)
 	return -1;
 }
 
-static u8 uniq_ioapic_id(u8 id)
+static u8 __init uniq_ioapic_id(u8 id)
 {
 #ifdef CONFIG_X86_32
 	if ((boot_cpu_data.x86_vendor == X86_VENDOR_INTEL) &&