Merge branch 'mctp-serial-tx-escapes'

Matt Johnston says:

====================
net: mctp-serial: Fix for missing tx escapes

The mctp-serial code to add escape characters was incorrect due to an
off-by-one error. This series adds a test for the chunking which splits
by escape characters, and fixes the bug.

v2: Fix kunit param const pointer
====================

Signed-off-by: David S. Miller <davem@davemloft.net>