s390/crypto: enable clear key values for paes ciphers

With this patch the paes ciphers do accept AES clear key values of
size 16, 24 or 32 byte. The key value is internal rearranged to form a
paes clear key token so that the pkey kernel module recognizes and
handles this key material as source for protected keys.

Using clear key material as a source for protected keys is a security
risc as the raw key material is kept in memory. However, so the AES
selftests provided with the testmanager can be run during registration
of the paes ciphers.

Signed-off-by: Harald Freudenberger <freude@linux.ibm.com>
Signed-off-by: Vasily Gorbik <gor@linux.ibm.com>