Most of the devices in OMAP family of SoCs are not using IOMMU. The
patch for converting the OMAP IOMMU to use generic IOMMU bus probe
functionality failed to add a check for this, so add it here.

Fixes: c822b37c ("iommu/omap: Remove orphan_dev tracking")
Reported-by: Tomi Valkeinen <tomi.valkeinen@ti.com>
Signed-off-by: Tero Kristo <t-kristo@ti.com>
Link: https://lore.kernel.org/r/20200518111057.23140-1-t-kristo@ti.comSigned-off-by: Joerg Roedel <jroedel@suse.de>