MAINTAINERS: Downgrade MIPS Boston to 'Odd Fixes', fix Paul Burton mail

MAINTAINERS: Downgrade MIPS Boston to 'Odd Fixes', fix Paul Burton mail

Paul's Wavecomp email has been bouncing for months. He told us
he "no longer has access to modern MIPS CPUs or Boston hardware,
and wouldn't currently have time to spend on them if he did." [1]
but "perhaps that might change in the future." [2].
Be fair and downgrade the status of the Boston board to "Odd Fixes"
(has a maintainer but they don't have time to do much other).
Similarly to commit 2b107c2c1c (".mailmap: Update Paul Burton email
address"), update his email address here too.

[1] https://www.mail-archive.com/qemu-devel@nongnu.org/msg718739.html
[2] https://www.mail-archive.com/qemu-devel@nongnu.org/msg728605.html

Signed-off-by: Philippe Mathieu-Daudé <f4bug@amsat.org>
Reviewed-by: Thomas Huth <thuth@redhat.com>
Message-Id: <20201013101659.3557154-4-f4bug@amsat.org>