crypto: caam - fix descriptor length adjustments for protocol descriptors

init_desc, by always ORing with 1 for the descriptor header inclusion
into the descriptor length, and init_sh_desc_pdb, by always specifying
the descriptor length modification for the PDB via options, would not
allow for odd length PDBs to be embedded in the constructed descriptor
length.  Fix this by simply changing the OR to an addition.

also round-up pdb_bytes to the next SEC command unit size, to
allow for, e.g., optional packet header bytes that aren't a
multiple of CAAM_CMD_SZ.

Reported-by: Radu-Andrei BULIE <radu.bulie@freescale.com>
Signed-off-by: Kim Phillips <kim.phillips@freescale.com>
Cc: Yashpal Dutta <yashpal.dutta@freescale.com>
Signed-off-by: Herbert Xu <herbert@gondor.apana.org.au>