drm/amd/display: Remove useless function call

[WHAT & HOW]
clk_mgr_helper_get_active_display_cnt returns display count and itself
alone has no use.

This fixes 1 CHECKED_RETURN issue reported by Coverity.
Reviewed-by: Rodrigo Siqueira <rodrigo.siqueira@amd.com>
Signed-off-by: Alex Hung <alex.hung@amd.com>
Tested-by: Daniel Wheeler <daniel.wheeler@amd.com>
Signed-off-by: Alex Deucher <alexander.deucher@amd.com>

drivers/gpu/drm/amd/display/dc/clk_mgr/dcn201/dcn201_clk_mgr.c

@@ -113,8 +113,6 @@ static void dcn201_update_clocks(struct clk_mgr *clk_mgr_base,
 		dcn2_read_clocks_from_hw_dentist(clk_mgr_base);
 	}
 
-	clk_mgr_helper_get_active_display_cnt(dc, context);
-
 	if (should_set_clock(safe_to_lower, new_clocks->phyclk_khz, clk_mgr_base->clks.phyclk_khz))
 		clk_mgr_base->clks.phyclk_khz = new_clocks->phyclk_khz;