s390/pkey: Add AES xts and HMAC clear key token support

Add support for deriving protected keys from clear key token for
AES xts and HMAC keys via PCKMO instruction. Add support for
protected key generation and unwrap of protected key tokens for
these key types. Furthermore 4 new sysfs attributes are introduced:

- /sys/devices/virtual/misc/pkey/protkey/protkey_aes_xts_128
- /sys/devices/virtual/misc/pkey/protkey/protkey_aes_xts_256
- /sys/devices/virtual/misc/pkey/protkey/protkey_hmac_512
- /sys/devices/virtual/misc/pkey/protkey/protkey_hmac_1024

Signed-off-by: Harald Freudenberger <freude@linux.ibm.com>
Reviewed-by: Ingo Franzki <ifranzki@linux.ibm.com>
Signed-off-by: Heiko Carstens <hca@linux.ibm.com>