KVM: s390: add SPDX identifiers to the remaining files

It's good to have SPDX identifiers in all files to make it easier to
audit the kernel tree for correct licenses.

Update the arch/s390/kvm/ files with the correct SPDX license
identifier based on the license text in the file itself.  The SPDX
identifier is a legally binding shorthand, which can be used instead of
the full boiler plate text.

This work is based on a script and data from Thomas Gleixner, Philippe
Ombredanne, and Kate Stewart.

Cc: Christian Borntraeger <borntraeger@de.ibm.com>
Cc: Cornelia Huck <cohuck@redhat.com>
Cc: Martin Schwidefsky <schwidefsky@de.ibm.com>
Cc: Heiko Carstens <heiko.carstens@de.ibm.com>
Cc: Thomas Gleixner <tglx@linutronix.de>
Cc: Kate Stewart <kstewart@linuxfoundation.org>
Cc: Philippe Ombredanne <pombredanne@nexb.com>
Signed-off-by: Greg Kroah-Hartman <gregkh@linuxfoundation.org>
Message-Id: <20171124140043.10062-3-gregkh@linuxfoundation.org>
Acked-by: Cornelia Huck <cohuck@redhat.com>
Signed-off-by: Christian Borntraeger <borntraeger@de.ibm.com>

arch/s390/kvm/Makefile

+# SPDX-License-Identifier: GPL-2.0
 # Makefile for kernel virtual machines on s390
 #
 # Copyright IBM Corp. 2008

arch/s390/kvm/diag.c

+// SPDX-License-Identifier: GPL-2.0
 /*
  * handling diagnose instructions
  *

arch/s390/kvm/gaccess.h

+/* SPDX-License-Identifier: GPL-2.0 */
 /*
  * access guest memory
  *

arch/s390/kvm/guestdbg.c

+// SPDX-License-Identifier: GPL-2.0
 /*
  * kvm guest debug support
  *

arch/s390/kvm/intercept.c

+// SPDX-License-Identifier: GPL-2.0
 /*
  * in-kernel handling for sie intercepts
  *

arch/s390/kvm/interrupt.c

+// SPDX-License-Identifier: GPL-2.0
 /*
  * handling kvm guest interrupts
  *

arch/s390/kvm/irq.h

+/* SPDX-License-Identifier: GPL-2.0 */
 /*
  * s390 irqchip routines
  *

arch/s390/kvm/kvm-s390.c

+// SPDX-License-Identifier: GPL-2.0
 /*
  * hosting zSeries kernel virtual machines
  *

arch/s390/kvm/kvm-s390.h

+/* SPDX-License-Identifier: GPL-2.0 */
 /*
  * definition for kvm on s390
  *

arch/s390/kvm/priv.c

+// SPDX-License-Identifier: GPL-2.0
 /*
  * handling privileged instructions
  *

arch/s390/kvm/sigp.c

+// SPDX-License-Identifier: GPL-2.0
 /*
  * handling interprocessor communication
  *

arch/s390/kvm/vsie.c

+// SPDX-License-Identifier: GPL-2.0
 /*
  * kvm nested virtualization support for s390x
  *