s390/crypto: Enhance paes cipher to accept variable length key material

Enhance the paes_s390 kernel module to allow the paes cipher to
accept variable length key material. The key material accepted by
the paes cipher is a key blob of various types. As of today, two
key blob types are supported: CCA secure key blobs and protected
key blobs.

Signed-off-by: Ingo Franzki <ifranzki@linux.ibm.com>
Reviewed-by: Harald Freudenberger <freude@linux.ibm.com>
Reviewed-by: Hendrik Brueckner <brueckner@linux.ibm.com>
Signed-off-by: Martin Schwidefsky <schwidefsky@de.ibm.com>