iommu/vt-d, trivial: clean sparse warnings

Clean up most sparse warnings in Intel DMA and interrupt remapping
drivers.

Signed-off-by: Jiang Liu <jiang.liu@linux.intel.com>
Signed-off-by: Joerg Roedel <joro@8bytes.org>
diff --git a/drivers/iommu/intel-iommu.c b/drivers/iommu/intel-iommu.c
index dec715c..948c6a0 100644
--- a/drivers/iommu/intel-iommu.c
+++ b/drivers/iommu/intel-iommu.c
@@ -382,7 +382,7 @@
 
 static void flush_unmaps_timeout(unsigned long data);
 
-DEFINE_TIMER(unmap_timer,  flush_unmaps_timeout, 0, 0);
+static DEFINE_TIMER(unmap_timer,  flush_unmaps_timeout, 0, 0);
 
 #define HIGH_WATER_MARK 250
 struct deferred_flush_tables {