Use msg_len_to_hash_in_bits for CMAC_BITLEN

Use new field msg_len_to_hash_in_bits (which is in a union,
shared with msg_len_to_hash_in_bytes), to
provide the length to hash for CMAC_BITLEN,
instead of using the specific field under the CMAC
structure within the job structure.

Change-Id: If9d41729020ef98573d033e3483e80bd9948090e