[WHY & HOW]
There is a problem in hscale_pixel_rate, the bug
causes DCN to be more optimistic (more likely to underflow)
in upscale cases during prefetch.
This commit ports the fix from DV code to address these issues.
Signed-off-by: Sung Lee <sung.lee@amd.com>
Reviewed-by: Dmytro Laktyushkin <Dmytro.Laktyushkin@amd.com>
Acked-by: Aurabindo Pillai <aurabindo.pillai@amd.com>
Signed-off-by: Alex Deucher <alexander.deucher@amd.com>