drm/amd/display: use CRTC_VERTICAL_INTERRUPT0 as VBLANK trigger.

VBLANK interrupt is driven bu line buffer vcounter which is
ahead of CRTC vcounter. Use an interrupt that fires at the actual
CRTC vblank start boundry.

Signed-off-by: Andrey Grodzovsky <Andrey.Grodzovsky@amd.com>
Acked-by: Harry Wentland <Harry.Wentland@amd.com>
Reviewed-by: Andrey Grodzovsky <Andrey.Grodzovsky@amd.com>
Signed-off-by: Alex Deucher <alexander.deucher@amd.com>