firewire: core: WARN on wrong usage of core transaction functions

In the code path which creates request packets, clearly mark a switch
branch which must never be reached with a WARN.

In the code path which creates response packets, replace a BUG by a
friendlier to debug WARN.

Signed-off-by: Stefan Richter <stefanr@s5r6.in-berlin.de>
1 file changed