drm/amd/display: Do not program interrupt status on disabled crtc

Prevent interrupt programming of a crtc on which the stream is disabled and
it doesn't have an OTG to reference.

Signed-off-by: Mikita Lipski <mikita.lipski@amd.com>
Reviewed-by: Harry Wentland <Harry.Wentland@amd.com>
Signed-off-by: Alex Deucher <alexander.deucher@amd.com>