Merge branch 'maintainers-update-entries-for-s390-network-driver-files'

Simon Horman says:

====================
MAINTAINERS: Update entries for s390 network driver files

Update the entries for s390 network driver files to:

* Add include/linux/ism.h to MAINTAINERS
* Add s390 network driver files to the NETWORKING DRIVERS section

This is to aid developers, and tooling such as get_maintainer.pl alike
to CC patches to all the appropriate people and mailing lists.  And is
in keeping with an ongoing effort for NETWORKING entries in MAINTAINERS
to more accurately reflect the way code is maintained.
====================

Link: https://patch.msgid.link/20250417-ism-maint-v1-0-b001be8545ce@kernel.org


Signed-off-by: Jakub Kicinski <kuba@kernel.org>