treewide: Add SPDX license identifier for missed files

Add SPDX license identifiers to all files which:

 - Have no license information of any form

 - Have EXPORT_.*_SYMBOL_GPL inside which was used in the
   initial scan/conversion to ignore the file

These files fall under the project license, GPL v2 only. The resulting SPDX
license identifier is:

  GPL-2.0-only

Signed-off-by: Thomas Gleixner <[email protected]>
Signed-off-by: Greg Kroah-Hartman <[email protected]>

Author: KAGA-KOKO

arch/arm/kernel/stacktrace.c

@@ -1,3 +1,4 @@
+// SPDX-License-Identifier: GPL-2.0-only
 #include <linux/export.h>
 #include <linux/sched.h>
 #include <linux/sched/debug.h>

arch/arm/mm/ioremap.c

@@ -1,3 +1,4 @@
+// SPDX-License-Identifier: GPL-2.0-only
 /*
  *  linux/arch/arm/mm/ioremap.c
  *

arch/arm/mm/nommu.c

@@ -1,3 +1,4 @@
+// SPDX-License-Identifier: GPL-2.0-only
 /*
  *  linux/arch/arm/mm/nommu.c
  *

arch/arm/xen/enlighten.c

@@ -1,3 +1,4 @@
+// SPDX-License-Identifier: GPL-2.0-only
 #include <xen/xen.h>
 #include <xen/events.h>
 #include <xen/grant_table.h>

arch/arm/xen/mm.c

@@ -1,3 +1,4 @@
+// SPDX-License-Identifier: GPL-2.0-only
 #include <linux/cpu.h>
 #include <linux/dma-mapping.h>
 #include <linux/gfp.h>

arch/arm/xen/p2m.c

@@ -1,3 +1,4 @@
+// SPDX-License-Identifier: GPL-2.0-only
 #include <linux/memblock.h>
 #include <linux/gfp.h>
 #include <linux/export.h>

arch/ia64/kernel/esi_stub.S

@@ -1,3 +1,4 @@
+/* SPDX-License-Identifier: GPL-2.0-only */
 /*
  * ESI call stub.
  *

arch/ia64/kernel/mca.c

@@ -1,3 +1,4 @@
+// SPDX-License-Identifier: GPL-2.0-only
 /*
  * File:	mca.c
  * Purpose:	Generic MCA handling layer

arch/ia64/kernel/perfmon.c

@@ -1,3 +1,4 @@
+// SPDX-License-Identifier: GPL-2.0-only
 /*
  * This file implements the perfmon-2 subsystem which is used
  * to program the IA-64 Performance Monitoring Unit (PMU).

arch/ia64/kernel/sal.c

@@ -1,3 +1,4 @@
+// SPDX-License-Identifier: GPL-2.0-only
 /*
  * System Abstraction Layer (SAL) interface routines.
  *