iommu/amd: Don't use IS_ERR_VALUE to check integer values

Use the better 'var < 0' check.

Fixes: 7aba6cb9ee9d ('iommu/amd: Make call-sites of get_device_id aware of its return value')
Signed-off-by: Joerg Roedel <jroedel@suse.de>
1 file changed