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]>

kernel/sched/clock.c

@@ -1,3 +1,4 @@
+// SPDX-License-Identifier: GPL-2.0-only
 /*
  * sched_clock() for unstable CPU clocks
  *

kernel/sched/core.c

@@ -1,3 +1,4 @@
+// SPDX-License-Identifier: GPL-2.0-only
 /*
  *  kernel/sched/core.c
  *

kernel/sched/cputime.c

@@ -1,3 +1,4 @@
+// SPDX-License-Identifier: GPL-2.0-only
 /*
  * Simple CPU accounting cgroup controller
  */

kernel/sched/idle.c

@@ -1,3 +1,4 @@
+// SPDX-License-Identifier: GPL-2.0-only
 /*
  * Generic entry points for the idle threads and
  * implementation of the idle task scheduling class.

kernel/sched/isolation.c

@@ -1,3 +1,4 @@
+// SPDX-License-Identifier: GPL-2.0-only
 /*
  *  Housekeeping management. Manage the targets for routine code that can run on
  *  any CPU: unbound workqueues, timers, kthreads and any offloadable work.

kernel/sched/wait.c

@@ -1,3 +1,4 @@
+// SPDX-License-Identifier: GPL-2.0-only
 /*
  * Generic waiting primitives.
  *

kernel/sched/wait_bit.c

@@ -1,3 +1,4 @@
+// SPDX-License-Identifier: GPL-2.0-only
 /*
  * The implementation of the wait_bit*() and related waiting APIs:
  */