iommu: Clean up of_iommu_init_fn

Now that no more drivers rely on arbitrary early initialisation via an
of_iommu_init_fn hook, let's clean up the redundant remnants. The
IOMMU_OF_DECLARE() macro needs to remain for now, as the probe-deferral
mechanism has no other nice way to detect built-in drivers before they
have registered themselves, such that it can make the right decision.

Reviewed-by: Sricharan R <sricharan@codeaurora.org>
Signed-off-by: Robin Murphy <robin.murphy@arm.com>
Signed-off-by: Joerg Roedel <jroedel@suse.de>

drivers/iommu/ipmmu-vmsa.c

@@ -1108,8 +1108,8 @@ static void __exit ipmmu_exit(void)
 subsys_initcall(ipmmu_init);
 module_exit(ipmmu_exit);
 
-IOMMU_OF_DECLARE(ipmmu_vmsa_iommu_of, "renesas,ipmmu-vmsa", NULL);
-IOMMU_OF_DECLARE(ipmmu_r8a7795_iommu_of, "renesas,ipmmu-r8a7795", NULL);
+IOMMU_OF_DECLARE(ipmmu_vmsa_iommu_of, "renesas,ipmmu-vmsa");
+IOMMU_OF_DECLARE(ipmmu_r8a7795_iommu_of, "renesas,ipmmu-r8a7795");
 
 MODULE_DESCRIPTION("IOMMU API for Renesas VMSA-compatible IPMMU");
 MODULE_AUTHOR("Laurent Pinchart <laurent.pinchart@ideasonboard.com>");