iommu: Fix kdocs of pci_dev_reset_iommu_done()

iommu: Fix kdocs of pci_dev_reset_iommu_done()

Remove the duplicated word. No functional change.

Fixes: c279e83953d9 ("iommu: Introduce pci_dev_reset_iommu_prepare/done()")
Reviewed-by: Shuai Xue <xueshuai@linux.alibaba.com>
Reviewed-by: Jason Gunthorpe <jgg@nvidia.com>
Reviewed-by: Kevin Tian <kevin.tian@intel.com>
Reviewed-by: Lu Baolu <baolu.lu@linux.intel.com>
Signed-off-by: Nicolin Chen <nicolinc@nvidia.com>
Signed-off-by: Joerg Roedel <joerg.roedel@amd.com>