media: MAINTAINERS: Remove Pawel from the maintainers list of videobuf2

According to [1], there has been no email related to videobuf2 posted
from him to the linux-media mailing list since Apr 2015.

Note: The linked archive seems to lack messages newer than the middle of
2019, but it is the only archive that offers search by name. A manual
look through the messages after that time confirms the observation.

[1] https://www.mail-archive.com/search?a=1&l=linux-media%40vger.kernel.org&haswords=&x=0&y=0&from=Pawel+Osciak&subject=&datewithin=1d&date=&notwords=&o=newest

Signed-off-by: Tomasz Figa <tfiga@chromium.org>
Signed-off-by: Hans Verkuil <hverkuil-cisco@xs4all.nl>
Signed-off-by: Mauro Carvalho Chehab <mchehab+huawei@kernel.org>