x86: introduce smpboot_clear_io_apic

x86_64 has two nr_ioapics = 0 statements. In 32-bit, it can be done
too. We do it through the smpboot_clear_io_apic() inline function,
to cope with subarchitectures (visws) that does not compile mpparse in

Signed-off-by: Glauber Costa <gcosta@redhat.com>
Signed-off-by: Ingo Molnar <mingo@elte.hu>
diff --git a/include/asm-x86/mach-default/smpboot_hooks.h b/include/asm-x86/mach-default/smpboot_hooks.h
index 8e1c6c0..3ff2c5b 100644
--- a/include/asm-x86/mach-default/smpboot_hooks.h
+++ b/include/asm-x86/mach-default/smpboot_hooks.h
@@ -44,3 +44,8 @@
 	else
 		nr_ioapics = 0;
 }
+
+static inline void smpboot_clear_io_apic(void)
+{
+	nr_ioapics = 0;
+}