[Why]
To support feature that calculates CRTC CRC value on specific
region (crc window).

[How]
1. Use debugfs to specify crtc crc window
2. Use vline0 IRQ to write crtc crc window

Signed-off-by: Wayne Lin <Wayne.Lin@amd.com>
Reviewed-by: Nicholas Kazlauskas <Nicholas.Kazlauskas@amd.com>
Acked-by: Eryk Brol <eryk.brol@amd.com>
Acked-by: Rodrigo Siqueira <Rodrigo.Siqueira@amd.com>
Signed-off-by: Alex Deucher <alexander.deucher@amd.com>