iommu/mediatek: Make it explicitly non-modular

The Kconfig currently controlling compilation of this code is:

drivers/iommu/Kconfig:config MTK_IOMMU_V1
drivers/iommu/Kconfig:  bool "MTK IOMMU Version 1 (M4U gen1) Support"

...meaning that it currently is not being built as a module by anyone.

Lets remove the modular code that is essentially orphaned, so that
when reading the driver there is no doubt it is builtin-only.

Since module_init was not even used by this driver, the init ordering
remains unchanged with this commit.

We also delete the MODULE_LICENSE tag etc. since all that information
was (or is now) contained at the top of the file in the comments.

Cc: Joerg Roedel <joro@8bytes.org>
Cc: Matthias Brugger <matthias.bgg@gmail.com>
Cc: Honghui Zhang <honghui.zhang@mediatek.com>
Cc: iommu@lists.linux-foundation.org
Cc: linux-mediatek@lists.infradead.org
Acked-by: Honghui Zhang <honghui.zhang@mediatek.com>
Signed-off-by: Paul Gortmaker <paul.gortmaker@windriver.com>
Signed-off-by: Joerg Roedel <jroedel@suse.de>

drivers/iommu/mtk_iommu_v1.c

 /*
+ * IOMMU API for MTK architected m4u v1 implementations
+ *
  * Copyright (c) 2015-2016 MediaTek Inc.
  * Author: Honghui Zhang <honghui.zhang@mediatek.com>
  *
@@ -35,7 +37,7 @@
 #include <linux/spinlock.h>
 #include <asm/barrier.h>
 #include <asm/dma-iommu.h>
-#include <linux/module.h>
+#include <linux/init.h>
 #include <dt-bindings/memory/mt2701-larb-port.h>
 #include <soc/mediatek/smi.h>
 #include "mtk_iommu.h"
@@ -704,15 +706,4 @@ static int __init m4u_init(void)
 {
 	return platform_driver_register(&mtk_iommu_driver);
 }
-
-static void __exit m4u_exit(void)
-{
-	return platform_driver_unregister(&mtk_iommu_driver);
-}
-
 subsys_initcall(m4u_init);
-module_exit(m4u_exit);
-
-MODULE_DESCRIPTION("IOMMU API for MTK architected m4u v1 implementations");
-MODULE_AUTHOR("Honghui Zhang <honghui.zhang@mediatek.com>");
-MODULE_LICENSE("GPL v2");