iommu: Clean up the comments for iommu_group_alloc

@name parameter has been removed.
Signed-off-by: Lu Baolu <baolu.lu@linux.intel.com>
Signed-off-by: Joerg Roedel <jroedel@suse.de>

drivers/iommu/iommu.c

@@ -324,7 +324,6 @@ static struct kobj_type iommu_group_ktype = {
 
 /**
  * iommu_group_alloc - Allocate a new group
- * @name: Optional name to associate with group, visible in sysfs
  *
  * This function is called by an iommu driver to allocate a new iommu
  * group.  The iommu group represents the minimum granularity of the iommu.