x86: Remove more unmodified io_apic_ops

io_apic_ops.init() is either NULL, if IO-APIC support is disabled at
compile time or native_io_apic_init_mappings(). No point to have that
as we can achieve the same thing with an empty inline.

Signed-off-by: Thomas Gleixner <tglx@linutronix.de>

arch/x86/kernel/apic/io_apic.c

@@ -2687,7 +2687,7 @@ static struct resource * __init ioapic_setup_resources(void)
 	return res;
 }
 
-void __init native_io_apic_init_mappings(void)
+void __init io_apic_init_mappings(void)
 {
 	unsigned long ioapic_phys, idx = FIX_IO_APIC_BASE_0;
 	struct resource *ioapic_res;