[pvr] fix internal group loading

As we never load the internal groups from our TV database, changing the group name in our group manager has no effect. This fixes the loading of the internal channel groups.
[pvr] cosmetics: refactor internal group id constants to be more meaningful
dxva: fix and rework video surface handling
dxva: let renderer control the render buffers
dxva: flush ffmpeg buffers if it holds any refs on close
renderer: rename/correct GetProcessorSize, processor is not exposed anymore
dxva: disable hq scalers for dxva rendering, it fails on NVdia. 3c31288b4708db2a2c9cc2dbd2b58de30f41290d
dxva: never try to open more than a single hw decoder on ati HD 2xxx and HD3xxx
DXVA-HD: return false if OpenProcessor fails
Merge pull request #5370 from FernetMenta/dxva

DXVA: fixes and rework
vaapi: flush ffmpeg buffers if it holds any refs on close
vaapi: drop unused member
renderer: bump number of buffers for vdpau and vaapi
[kodi] add splash with (TM)
Merge pull request #5391 from FernetMenta/vaapivdpau

Vaapivdpau: fix and optimization
[win32] fix detection of old XBMC install and remove XBMC regkeys
[win32] show message in installer that userdata was moved to new location
Merge pull request #5376 from xhaggi/pvr-fix-internal-group-loading

[pvr] fix internal group loading