clk: rockchip: mark pclk_ddrupctl as critical_clock on rk3036

No driver to handle this clk yet, but chip design requiress for this clock
supplying the ddr controller to be always on.

Signed-off-by: Elaine Zhang <zhangqing@rock-chips.com>
Signed-off-by: Heiko Stuebner <heiko@sntech.de>

drivers/clk/rockchip/clk-rk3036.c

@@ -436,6 +436,7 @@ static const char *const rk3036_critical_clocks[] __initconst = {
 	"aclk_peri",
 	"hclk_peri",
 	"pclk_peri",
+	"pclk_ddrupctl",
 };
 
 static void __init rk3036_clk_init(struct device_node *np)