drm/bridge: dw-hdmi: add better clock disable control

drm/bridge: dw-hdmi: add better clock disable control

The video setup path aways sets the clock disable register to a specific
value, which has the effect of disabling the CEC engine.  When we add the
CEC driver, this becomes a problem.

Fix this by only setting/clearing the bits that the video path needs to.

Reviewed-by: Jose Abreu <[email protected]>
Signed-off-by: Russell King <[email protected]>
Tested-by: Laurent Pinchart <[email protected]>
Acked-by: Hans Verkuil <[email protected]>
Signed-off-by: Archit Taneja <[email protected]>
Link: https://patchwork.freedesktop.org/patch/msgid/[email protected]