ACPI/IORT: Add support for IOMMU fwnode registration

ACPI/IORT: Add support for IOMMU fwnode registration

The ACPI IORT table provide entries for IOMMU (aka SMMU in ARM world)
components that allow creating the kernel data structures required to
probe and initialize the IOMMU devices.

This patch provides support in the IORT kernel code to register IOMMU
components and their respective fwnode.

Signed-off-by: Lorenzo Pieralisi <lorenzo.pieralisi@arm.com>
Reviewed-by: Hanjun Guo <hanjun.guo@linaro.org>
Reviewed-by: Tomasz Nowicki <tn@semihalf.com>
Tested-by: Hanjun Guo <hanjun.guo@linaro.org>
Tested-by: Tomasz Nowicki <tn@semihalf.com>
Cc: Hanjun Guo <hanjun.guo@linaro.org>
Cc: Tomasz Nowicki <tn@semihalf.com>
Cc: "Rafael J. Wysocki" <rjw@rjwysocki.net>
Signed-off-by: Will Deacon <will.deacon@arm.com>