crypto: caam - add PDB (Protocol Descriptor Block) definitions

Add a PDB header file to support building protocol descriptors.

Signed-off-by: Steve Cornelius <sec@pobox.com>
Signed-off-by: Hemant Agrawal <hemant@freescale.com>
Signed-off-by: Kim Phillips <kim.phillips@freescale.com>
Signed-off-by: Herbert Xu <herbert@gondor.apana.org.au>