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As we only allow the use of a disabled CRTC, we don't need to handle the
case where we are reusing an already enabled pipe.
Signed-off-by: Chris Wilson <chris@chris-wilson.co.uk>
Reviewed-by: Keith Packard <keithp@keithp.com>
Signed-off-by: Keith Packard <keithp@keithp.com>