x86: build fix for "x86: fix C1E && nx6325 stability problem"

fix:

 arch/x86/kernel/built-in.o: In function `dmi_ignore_irq0_timer_override':
 boot.c:(.init.text+0x3ea4): undefined reference to `force_mask_ioapic_irq_2'
Signed-off-by: NIngo Molnar <mingo@elte.hu>

include/asm-x86/genapic_32.h

@@ -119,6 +119,10 @@ enum uv_system_type {UV_NONE, UV_LEGACY_APIC, UV_X2APIC, UV_NON_UNIQUE_APIC};
 #define is_uv_system()			0
 #define uv_wakeup_secondary(a, b)	1
 
+#ifdef CONFIG_X86_IO_APIC
 extern void force_mask_ioapic_irq_2(void);
+#else
+static inline void force_mask_ioapic_irq_2(void) { }
+#endif
 
 #endif

include/asm-x86/genapic_64.h

@@ -46,6 +46,10 @@ extern int uv_wakeup_secondary(int phys_apicid, unsigned int start_rip);
 
 extern void setup_apic_routing(void);
 
+#ifdef CONFIG_X86_IO_APIC
 extern void force_mask_ioapic_irq_2(void);
+#else
+static inline void force_mask_ioapic_irq_2(void) { }
+#endif
 
 #endif