drm/amd/display: always program DPPDTO unless not safe to lower

[Why]
We defer clock updates to after pipes have been programmed. In
some instances we use DPPCLK that have been previously set to be
"unused". This results in a brief window of time where underflow
could occur.

[How]
During prepare bandwidth allow rn_update_clocks_update_dpp_dto
to check each instance and compare previous clock to new clock.
If new clock is higher than previous clock, program DPPDTO.
Signed-off-by: Jake Wang <haonan.wang2@amd.com>
Acked-by: Bindu Ramamurthy <bindu.r@amd.com>
Signed-off-by: Alex Deucher <alexander.deucher@amd.com>

drivers/gpu/drm/amd/display/dc/clk_mgr/dcn21/rn_clk_mgr.c

@@ -227,12 +227,11 @@ void rn_update_clocks(struct clk_mgr *clk_mgr_base,
 					rn_vbios_smu_set_dppclk(clk_mgr, clk_mgr_base->clks.dppclk_khz);
 
 		// always update dtos unless clock is lowered and not safe to lower
-		if (new_clocks->dppclk_khz >= dc->current_state->bw_ctx.bw.dcn.clk.dppclk_khz)
-			rn_update_clocks_update_dpp_dto(
-					clk_mgr,
-					context,
-					clk_mgr_base->clks.actual_dppclk_khz,
-					safe_to_lower);
+		rn_update_clocks_update_dpp_dto(
+				clk_mgr,
+				context,
+				clk_mgr_base->clks.actual_dppclk_khz,
+				safe_to_lower);
 	}
 
 	if (update_dispclk &&