MAINTAINERS: Change Meta arch port status to Odd Fixes

For a while now the Meta architecture port has been supported with only
odd fixes rather than any big new features, since it has now been
effectively supersceded by MIPS, and there is no prospect of any new
products being based on it. Change the maintenance status to Odd Fixes
in order to reflect reality.

Signed-off-by: James Hogan <james.hogan@imgtec.com>
Cc: linux-metag@vger.kernel.org