library/PCUIF_Types: use PADDING attribute for 'PCUIF_Message'

PCUIFv9 compatibility has been dropped in [1], so now we can tell
TITAN's RAW codec what kind of padding to expect in received
messages and to append to encoded messages.  This eliminates
thousands of warnings about unhandled tail octets.

Change-Id: Id5ab587f7984a91f3603efc5d427aa4cb4fa6757
Related: [1] Ia9f366ca1fdad700a90ca3367e43523f7bac39a1
Related: OS#5083
2 files changed