x86: apic.c x2apic_preenabled and disable_x2apic should be static

Impact: cleanup, reduce kernel size a bit, avoid sparse warning

Fixes sparse warning:

  arch/x86/kernel/apic.c:103:5: warning: symbol 'disable_x2apic' was not declared. Should it be static?

Signed-off-by: Jaswinder Singh <jaswinder@infradead.org>
Signed-off-by: Ingo Molnar <mingo@elte.hu>
diff --git a/arch/x86/include/asm/apic.h b/arch/x86/include/asm/apic.h
index 25caa07..e644bf6 100644
--- a/arch/x86/include/asm/apic.h
+++ b/arch/x86/include/asm/apic.h
@@ -93,7 +93,7 @@
 }
 
 #ifndef CONFIG_X86_32
-extern int x2apic, x2apic_preenabled;
+extern int x2apic;
 extern void check_x2apic(void);
 extern void enable_x2apic(void);
 extern void enable_IR_x2apic(void);