iommu/arm-smmu: Switch to subsys_initcall for driver registration

This should ensure that arm-smmu is initialized before other drivers
start handling devices that propably need smmu support.

Signed-off-by: Andreas Herrmann <andreas.herrmann@calxeda.com>
Signed-off-by: Will Deacon <will.deacon@arm.com>

drivers/iommu/arm-smmu.c

@@ -1976,7 +1976,7 @@ static void __exit arm_smmu_exit(void)
 	return platform_driver_unregister(&arm_smmu_driver);
 }
 
-module_init(arm_smmu_init);
+subsys_initcall(arm_smmu_init);
 module_exit(arm_smmu_exit);
 
 MODULE_DESCRIPTION("IOMMU API for ARM architected SMMU implementations");