s390: crypto: 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/crypto/ 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: Herbert Xu <herbert@gondor.apana.org.au>
Cc: "David S. Miller" <davem@davemloft.net>
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>
Signed-off-by: Martin Schwidefsky <schwidefsky@de.ibm.com>

arch/s390/crypto/aes_s390.c

+// SPDX-License-Identifier: GPL-2.0+
 /*
  * Cryptographic API.
  *

arch/s390/crypto/arch_random.c

+// SPDX-License-Identifier: GPL-2.0
 /*
  * s390 arch random implementation.
  *

arch/s390/crypto/crc32-vx.c

+// SPDX-License-Identifier: GPL-2.0
 /*
  * Crypto-API module for CRC-32 algorithms implemented with the
  * z/Architecture Vector Extension Facility.

arch/s390/crypto/des_s390.c

+// SPDX-License-Identifier: GPL-2.0+
 /*
  * Cryptographic API.
  *

arch/s390/crypto/ghash_s390.c

+// SPDX-License-Identifier: GPL-2.0
 /*
  * Cryptographic API.
  *

arch/s390/crypto/paes_s390.c

+// SPDX-License-Identifier: GPL-2.0
 /*
  * Cryptographic API.
  *

arch/s390/crypto/prng.c

+// SPDX-License-Identifier: GPL-2.0
 /*
  * Copyright IBM Corp. 2006, 2015
  * Author(s): Jan Glauber <jan.glauber@de.ibm.com>

arch/s390/crypto/sha.h

+/* SPDX-License-Identifier: GPL-2.0+ */
 /*
  * Cryptographic API.
  *

arch/s390/crypto/sha256_s390.c

+// SPDX-License-Identifier: GPL-2.0+
 /*
  * Cryptographic API.
  *

arch/s390/crypto/sha512_s390.c

+// SPDX-License-Identifier: GPL-2.0+
 /*
  * Cryptographic API.
  *

arch/s390/crypto/sha_common.c

+// SPDX-License-Identifier: GPL-2.0+
 /*
  * Cryptographic API.
  *