x2apic/intr-remap: decouple interrupt remapping from x2apic

interrupt remapping must be enabled before enabling x2apic, but
interrupt remapping doesn't depend on x2apic, it can be used
separately. Enable interrupt remapping in init_dmars even x2apic
is not supported.

[dwmw2: Update Kconfig accordingly, fix build with INTR_REMAP && !X2APIC]

Signed-off-by: Weidong Han <weidong.han@intel.com>
Acked-by: Ingo Molnar <mingo@elte.hu>
Signed-off-by: David Woodhouse <David.Woodhouse@intel.com>
diff --git a/arch/x86/include/asm/apic.h b/arch/x86/include/asm/apic.h
index f9f0866..42f2f83 100644
--- a/arch/x86/include/asm/apic.h
+++ b/arch/x86/include/asm/apic.h
@@ -107,11 +107,10 @@
 extern void native_apic_icr_write(u32 low, u32 id);
 extern u64 native_apic_icr_read(void);
 
-#ifdef CONFIG_X86_X2APIC
-
 #define EIM_8BIT_APIC_ID	0
 #define EIM_32BIT_APIC_ID	1
 
+#ifdef CONFIG_X86_X2APIC
 /*
  * Make previous memory operations globally visible before
  * sending the IPI through x2apic wrmsr. We need a serializing instruction or