of: Add convenience wrappers for of_map_id()

of: Add convenience wrappers for of_map_id()

Since we now have quite a few users parsing "iommu-map" and "msi-map"
properties, give them some wrappers to conveniently encapsulate the
appropriate sets of property names. This will also make it easier to
then change of_map_id() to correctly account for specifier cells.

Reviewed-by: Rob Herring (Arm) <robh@kernel.org>
Reviewed-by: Frank Li <Frank.Li@nxp.com>
Acked-by: Marc Zyngier <maz@kernel.org>
Acked-by: Bjorn Helgaas <bhelgaas@google.com>
Signed-off-by: Robin Murphy <robin.murphy@arm.com>
Signed-off-by: Vijayanand Jitta <vijayanand.jitta@oss.qualcomm.com>
Link: https://patch.msgid.link/20260603-parse_iommu_cells-v16-1-dc509dacb19a@oss.qualcomm.com
Signed-off-by: Rob Herring (Arm) <robh@kernel.org>