MAINTAINERS: change BTTV status to Odd fixes

There aren't many things happening at bttv side for a long time:
Driver works, and it is stable. When new patches are submitted,
they're new boards addition for hardware I don't have. So,
move its status to Odd fixes to better reflect it.

Signed-off-by: Mauro Carvalho Chehab <mchehab@redhat.com>