iommu: Fix some W=1 warnings

The code is mostly free of W=1 warning, so fix the following:

drivers/iommu/iommu.c:996: warning: expecting prototype for iommu_group_for_each_dev(). Prototype was for __iommu_group_for_each_dev() instead
drivers/iommu/iommu.c:3048: warning: Function parameter or member 'drvdata' not described in 'iommu_sva_bind_device'
drivers/iommu/ioasid.c:354: warning: Function parameter or member 'ioasid' not described in 'ioasid_get'
drivers/iommu/omap-iommu.c:1098: warning: expecting prototype for omap_iommu_suspend_prepare(). Prototype was for omap_iommu_prepare() instead

Signed-off-by: John Garry <john.garry@huawei.com>
Reviewed-by: Robin Murphy <robin.murphy@arm.com>
Link: https://lore.kernel.org/r/1643366673-26803-1-git-send-email-john.garry@huawei.com


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