iommu/amd: Remove unused variable

The iommu variable in set_device_exclusion_range() us unused
now and causes a compiler warning. Remove it.

Fixes: 387caf0b ("iommu/amd: Treat per-device exclusion ranges as r/w unity-mapped regions")
Signed-off-by: Joerg Roedel <jroedel@suse.de>

drivers/iommu/amd_iommu_init.c

@@ -1118,8 +1118,6 @@ static int __init add_early_maps(void)
  */
 static void __init set_device_exclusion_range(u16 devid, struct ivmd_header *m)
 {
-	struct amd_iommu *iommu = amd_iommu_rlookup_table[devid];
-
 	if (!(m->flags & IVMD_FLAG_EXCL_RANGE))
 		return;