[$] DVB, header files, and user-space regressions

A regression that was recently reported for 5.14 in the mediasubsystem is a bit of a strange beast. The kernel's user-space binary interface (ABI) was not changed, which is the usual test for a patch to getreverted, but the report still led to a reversion. The change did lead toproblems building a user-space application because it moved some headerfiles to staging/ as part of a cleanup for a deprecated-thoughapparently still functioning-driver for a DigitalVideo Broadcasting (DVB) device. There are a few different issuestangled together here, but the reversion of a regression in the user-spaceAPI (and not ABI) is a new wrinkle.