message/pack: Allow packing payloads

Some IPMI handlers need the ability to support variable return types.
The easiest way to do that is to be able to return payloads and pack
them into the final payload.

Change-Id: I5098a1ab0998ada712096929eae40a3c88a6dea0
Signed-off-by: William A. Kennington III <wak@google.com>
2 files changed