drm/amd/display: Increase stutter watermark for dcn302 and dcn303

[Why]
Current watermarks end up programming lowers watermarks which
results in screen flickering and underflow for certain modes like 1440p.

[How]
Add 11us to stutter exit & stutter enter plus exit watermark.

Signed-off-by: Aurabindo Pillai <aurabindo.pillai@amd.com>
Reviewed-by: Jun Lei <jun.lei@amd.com>
Acked-by: Rodrigo Siqueira <Rodrigo.Siqueira@amd.com>
Signed-off-by: Alex Deucher <alexander.deucher@amd.com>