ACPI/IORT: Add function to check SMMUs drivers presence
The IOMMU probe deferral implementation requires a mechanism to detect
if drivers for SMMU components are built-in in the kernel to detect
whether IOMMU configuration for a given device should be deferred (ie
SMMU drivers present but still not probed) or not (drivers not present).
Add a simple function to IORT to detect if SMMU drivers for SMMU
components managed by IORT are built-in in the kernel.
Tested-by: Hanjun Guo <hanjun.guo@linaro.org> Signed-off-by: Lorenzo Pieralisi <lorenzo.pieralisi@arm.com> Reviewed-by: Robin Murphy <robin.murphy@arm.com> Cc: Sricharan R <sricharan@codeaurora.org> Signed-off-by: Joerg Roedel <jroedel@suse.de>