drm/amd/display: Added case for when RR equals panel's max RR using freesync

drm/amd/display: Added case for when RR equals panel's max RR using freesync

[WHY]
Rounding error sometimes occurs when the refresh rate is equal to a panel's
max refresh rate, causing HDMI compliance failures.

[HOW]
Added a case so that we round up to avoid v_total_min to be below a panel's
minimum bound.

Reviewed-by: Jun Lei <jun.lei@amd.com>
Signed-off-by: Harold Sun <Harold.Sun@amd.com>
Signed-off-by: Ray Wu <ray.wu@amd.com>
Tested-by: Daniel Wheeler <daniel.wheeler@amd.com>
Signed-off-by: Alex Deucher <alexander.deucher@amd.com>