Merge branch 'add-checks-for-incoming-packet-addresses'

Jeremy Kerr says:

====================
Add checks for incoming packet addresses

This series adds a couple of checks for valid addresses on incoming MCTP
packets. We introduce a couple of helpers in 1/2, and use them in the
ingress path in 2/2.
====================

Link: https://lore.kernel.org/r/20220218042554.564787-1-jk@codeconstruct.com.au
Signed-off-by: Jakub Kicinski <kuba@kernel.org>