x86, irq: Move irq_remapping_enabled declaration to iommu code

Remove the last left-over from this flag from x86 code.

Signed-off-by: Joerg Roedel <joro@8bytes.org>
Acked-by: Sebastian Andrzej Siewior <sebastian@breakpoint.cc>
Reviewed-by: Konrad Rzeszutek Wilk <konrad.wilk@oracle.com>
diff --git a/drivers/iommu/dmar.c b/drivers/iommu/dmar.c
index 86e2f4a..174bb65 100644
--- a/drivers/iommu/dmar.c
+++ b/drivers/iommu/dmar.c
@@ -41,6 +41,8 @@
 #include <asm/irq_remapping.h>
 #include <asm/iommu_table.h>
 
+#include "irq_remapping.h"
+
 /* No locks are needed as DMA remapping hardware unit
  * list is constructed at boot time and hotplug of
  * these units are not supported by the architecture.