[media] dt3155: move out of staging into drivers/media/pci

The dt3155 code is now in good shape, so move it out of staging into
drivers/media/pci. Mark in MAINTAINERS that I'll do Odd Fixes for this
driver.

Signed-off-by: Hans Verkuil <hans.verkuil@cisco.com>
Signed-off-by: Mauro Carvalho Chehab <mchehab@osg.samsung.com>