MAINTAINERS: Add an obsolete entry for LL TEMAC driver

LL TEMAC IP is no longer supported. Hence add an entry marking the
driver as obsolete.

Signed-off-by: Harini Katakam <harini.katakam@amd.com>
Link: https://lore.kernel.org/r/20230920115047.31345-1-harini.katakam@amd.com


Signed-off-by: Paolo Abeni <pabeni@redhat.com>