iommu: vsi: avoid -Wformat-security warning

iommu: vsi: avoid -Wformat-security warning

When -Wformat-security is enabled, it catches a call to
iommu_device_sysfs_add() that passes a string variable in
place of a format:

drivers/iommu/vsi-iommu.c: In function 'vsi_iommu_probe':
drivers/iommu/vsi-iommu.c:717:9: error: format not a string literal and no format arguments [-Werror=format-security]
  717 |         err = iommu_device_sysfs_add(&iommu->iommu, dev, NULL, dev_name(dev));
      |         ^~~

Pass this indirectly using "%s" as the format instead.

Fixes: 917ace84b770 ("iommu: Add verisilicon IOMMU driver")
Signed-off-by: Arnd Bergmann <arnd@arndb.de>
Reviewed-by: Benjamin Gaignard <benjamin.gaignard@collabora.com>
Signed-off-by: Joerg Roedel <joerg.roedel@amd.com>