ARM: OMAP: make iommu subsys_initcall to fix builtin omap3isp

omap3isp depends on omap's iommu and will fail to probe if
initialized before it (which always happen if they are builtin).

Make omap's iommu subsys_initcall as an interim solution until
the probe deferral mechanism is merged.
Reported-by: James <angweiyang@gmail.com>
Debugged-by: Laurent Pinchart <laurent.pinchart@ideasonboard.com>
Signed-off-by: Ohad Ben-Cohen <ohad@wizery.com>
Cc: stable <stable@vger.kernel.org>
Cc: Tony Lindgren <tony@atomide.com>
Cc: Hiroshi Doyu <hdoyu@nvidia.com>
Cc: Joerg Roedel <Joerg.Roedel@amd.com>
Signed-off-by: Joerg Roedel <joerg.roedel@amd.com>

arch/arm/mach-omap2/mailbox.c

@@ -412,7 +412,8 @@ static void __exit omap2_mbox_exit(void)
 	platform_driver_unregister(&omap2_mbox_driver);
 }
 
-module_init(omap2_mbox_init);
+/* must be ready before omap3isp is probed */
+subsys_initcall(omap2_mbox_init);
 module_exit(omap2_mbox_exit);
 
 MODULE_LICENSE("GPL v2");

drivers/iommu/omap-iommu.c

@@ -1223,7 +1223,8 @@ static int __init omap_iommu_init(void)
 
 	return platform_driver_register(&omap_iommu_driver);
 }
-module_init(omap_iommu_init);
+/* must be ready before omap3isp is probed */
+subsys_initcall(omap_iommu_init);
 
 static void __exit omap_iommu_exit(void)
 {