media: MAINTAINERS: Add myself as CAMSS maintainer

I discussed with Robert a few ago lending a hand with CAMSS. Following up
on that discussion, I'm happy to help.

Signed-off-by: Bryan O'Donoghue <bryan.odonoghue@linaro.org>
Reviewed-by: Robert Foss <rfoss@kernel.org>
Signed-off-by: Hans Verkuil <hverkuil-cisco@xs4all.nl>
Signed-off-by: Mauro Carvalho Chehab <mchehab@kernel.org>