owners: create IEEE 802.15.4 entry
Part of 802.15.4 was already excluded from networking, exclude the rest.
Create a separate entry 802.15.4 - we ship it, so we need a maintainer. Chris was nice enough to volunteer.
Cc: Chris von Recklinghausen crecklin@redhat.com Signed-off-by: Jiri Benc jbenc@redhat.com