iommu/exynos: Checking a device_link_add() call in exynos_iommu_add_device()

[Markus Elfring]

Hello,

I tried another script for the semantic patch language out.
This source code analysis approach points out that the implementation
of the function âexynos_iommu_add_deviceâ contains still
an unchecked call of the function âdevice_link_addâ.
https://git.kernel.org/pub/scm/linux/kernel/git/torvalds/linux.git/tree/drivers/iommu/exynos-iommu.c?id=0e2adab6cf285c41e825b6c74a3aa61324d1132c#n1253
https://elixir.bootlin.com/linux/v5.4-rc2/source/drivers/iommu/exynos-iommu.c#L1253

How do you think about to improve it?

* Which error code would you like to return for a failed
  device link addition at this place?

* Will it be needed to delete any links as exception handling?

Regards,
Markus