iommu/amd: Remove local variables

The usage of the local variables 'range' and 'misc' was removed
from commit 226e889b ("iommu/amd: Remove first/last_device handling")
and commit 23c742db ("iommu/amd: Split out PCI related parts of
IOMMU initialization"). So, remove them accrodingly.

Signed-off-by: Adrian Huang <ahuang12@lenovo.com>
Signed-off-by: Joerg Roedel <jroedel@suse.de>