iommu/amd: Fix sparse warning

CHECK   drivers/iommu/amd/iommu.c
drivers/iommu/amd/iommu.c:73:24: warning: symbol 'amd_iommu_ops' was not declared. Should it be static?

Signed-off-by: Vasant Hegde <vasant.hegde@amd.com>
Link: https://lore.kernel.org/r/20220912063248.7909-6-vasant.hegde@amd.com


Signed-off-by: Joerg Roedel <jroedel@suse.de>