drm/amd/display: set dpp dto as per requested clk for lower case.

[Why]
Blue screen when PNP with multiple monitor or hotplug external monitor when playing video
due to dpp dto isn't programmed properly.
If lower dpp clock, dpp dto need to be programmed first, and actual dpp clk not avalable yet.

[How]
set dpp dto as per request clk for lower case before dpp clk update, and after dpp clk updated
set dpp dto again with actual dpp clk.

Signed-off-by: Yongqiang Sun <yongqiang.sun@amd.com>
Acked-by: Bindu Ramamurthy <bindu.r@amd.com>
Signed-off-by: Alex Deucher <alexander.deucher@amd.com>