media: MAINTAINERS: media: Add Tomasz Figa as a videobuf2 reviewer

I tend to review most of the vb2 patches anyway and we need some active
reviewers, so let add me to the MAINTAINERS file as such.

Signed-off-by: Tomasz Figa <tfiga@chromium.org>
Acked-by: Marek Szyprowski <m.szyprowski@samsung.com>
Signed-off-by: Hans Verkuil <hverkuil-cisco@xs4all.nl>
Signed-off-by: Mauro Carvalho Chehab <mchehab+samsung@kernel.org>