drm/amd/display: Check for dmcu initialization before calling dmcu

[Why]
DMCU firmware is not required - the system is expected to run
fine without it.  Therefore, wherever dmcu functions could be
called, dmcu initialization shoudl be checked

[How]
Use the helpful hook dmcu_funcs->is_dmcu_initialized
Signed-off-by: David Francis <David.Francis@amd.com>
Reviewed-by: Hersen Wu <hersenxs.wu@amd.com>
Acked-by: Bhawanpreet Lakha <Bhawanpreet.Lakha@amd.com>
Signed-off-by: Alex Deucher <alexander.deucher@amd.com>

drivers/gpu/drm/amd/display/dc/core/dc_link.c

@@ -2218,7 +2218,7 @@ bool dc_link_set_psr_enable(const struct dc_link *link, bool enable, bool wait)
 	struct dc  *core_dc = link->ctx->dc;
 	struct dmcu *dmcu = core_dc->res_pool->dmcu;
 
-	if (dmcu != NULL && link->psr_enabled)
+	if ((dmcu != NULL && dmcu->funcs->is_dmcu_initialized(dmcu)) && link->psr_enabled)
 		dmcu->funcs->set_psr_enable(dmcu, enable, wait);
 
 	return true;

drivers/gpu/drm/amd/display/dc/dce/dce_clk_mgr.c

@@ -277,6 +277,7 @@ static int dce_set_clock(
 	if (requested_clk_khz == 0)
 		clk_mgr_dce->cur_min_clks_state = DM_PP_CLOCKS_STATE_NOMINAL;
 
+	if (dmcu && dmcu->funcs->is_dmcu_initialized(dmcu))
 		dmcu->funcs->set_psr_wait_loop(dmcu, actual_clock / 1000 / 7);
 
 	return actual_clock;
@@ -324,10 +325,12 @@ int dce112_set_clock(struct clk_mgr *clk_mgr, int requested_clk_khz)
 	bp->funcs->set_dce_clock(bp, &dce_clk_params);
 
 	if (!IS_FPGA_MAXIMUS_DC(core_dc->ctx->dce_environment)) {
+		if (dmcu && dmcu->funcs->is_dmcu_initialized(dmcu)) {
 			if (clk_mgr_dce->dfs_bypass_disp_clk != actual_clock)
 				dmcu->funcs->set_psr_wait_loop(dmcu,
 						actual_clock / 1000 / 7);
 		}
+	}
 
 	clk_mgr_dce->dfs_bypass_disp_clk = actual_clock;
 	return actual_clock;