Paul Bolle says:

====================
ser_gigaset: fix deallocation of platform device structure

Sascha Levin reported that the syzkaller fuzzer triggered a WARNING in
ser_gigaset (see https://lkml.kernel.org/g/56587467.8050102@oracle.com

 ). It
turned out that ser_gigaset has always deallocated its platform device
structure incorrectly. Tilman submitted the patch that fixes that (3/4) and a
related cleanup (4/4).

Tilman also submitted a minor cleanup of some NULL checks (1/4) that prompted
Alan to turn those checks into WARN_ONs (2/4). If no one hits these WARN_ONs in
the next couple of releases these WARN_ONs should be removed.
====================

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