drm/amd/display: Increase ips2_eval delay for DCN35

[Why]
New worst-case measurement observed at 1897us.

[How]
Increase to 2000us to cover the new worst case + margin.

Reviewed-by: Ovidiu Bunea <ovidiu.bunea@amd.com>
Acked-by: Aurabindo Pillai <aurabindo.pillai@amd.com>
Signed-off-by: Nicholas Kazlauskas <nicholas.kazlauskas@amd.com>
Tested-by: Daniel Wheeler <daniel.wheeler@amd.com>
Signed-off-by: Alex Deucher <alexander.deucher@amd.com>