MAINTAINERS: remove historic section DEVICE NUMBER REGISTRY

As described in Documentation/admin-guide/devices.rst, the device number
registry (or linux device list) is at Documentation/admin-guide/devices.txt
and no longer maintained at lanana.org.

The devices.txt file is basically community-maintained, and there is no
other dedicated maintainer or contact for that file nowadays.

Remove the historic section DEVICE NUMBER REGISTRY in MAINTAINERS.

Signed-off-by: Lukas Bulwahn <lukas.bulwahn@gmail.com>
Link: https://lore.kernel.org/r/20230307144000.29539-2-lukas.bulwahn@gmail.com


Signed-off-by: Jonathan Corbet <corbet@lwn.net>