iommu/vt-d: Define counter explicitly as unsigned int

iommu/vt-d: Define counter explicitly as unsigned int

Avoid below checkpatch warning.

WARNING: Prefer 'unsigned int' to bare use of 'unsigned'
+       unsigned        iommu_refcnt[DMAR_UNITS_SUPPORTED];

Fixes: 29a27719abaa ("iommu/vt-d: Replace iommu_bmp with a refcount")
Signed-off-by: Parav Pandit <parav@nvidia.com>
Signed-off-by: Lu Baolu <baolu.lu@linux.intel.com>
Link: https://lore.kernel.org/r/20210530075053.264218-1-parav@nvidia.com
Link: https://lore.kernel.org/r/20210610020115.1637656-23-baolu.lu@linux.intel.com
Signed-off-by: Joerg Roedel <jroedel@suse.de>