[PATCH 02/11] iommu: Use iommu_group_ref_get/put() for dev->iommu_group

[Tian, Kevin]

> From: Jason Gunthorpe <jgg at nvidia.com>
> Sent: Thursday, April 20, 2023 12:12 AM
> 
> No reason to open code this, use the proper helper functions.
> 
> Signed-off-by: Jason Gunthorpe <jgg at nvidia.com>

Reviewed-by: Kevin Tian <kevin.tian at intel.com>