soc: rockchip: power-domain: Add a sanity check on pd->num_clks

The of_count_phandle_with_args() can fail and return error(for example,
rk3399 pd_vio doesn't have clocks). That would break the pd probe.

Add a sanity check on pd->num_clks to avoid that.

Fixes: 65084121d59d ("soc: rockchip: power-domain: use clk_bulk APIs")
Reported-by: Shawn Lin <shawn.lin@rock-chips.com>
Signed-off-by: Jeffy Chen <jeffy.chen@rock-chips.com>
Tested-by: Shawn Lin <shawn.lin@rock-chips.com>
Signed-off-by: Heiko Stuebner <heiko@sntech.de>

drivers/soc/rockchip/pm_domains.c

@@ -402,11 +402,16 @@ static int rockchip_pm_add_one_domain(struct rockchip_pmu *pmu,
 
 	pd->num_clks = of_count_phandle_with_args(node, "clocks",
 						  "#clock-cells");
-
-	pd->clks = devm_kcalloc(pmu->dev, pd->num_clks, sizeof(*pd->clks),
-				GFP_KERNEL);
-	if (!pd->clks)
-		return -ENOMEM;
+	if (pd->num_clks > 0) {
+		pd->clks = devm_kcalloc(pmu->dev, pd->num_clks,
+					sizeof(*pd->clks), GFP_KERNEL);
+		if (!pd->clks)
+			return -ENOMEM;
+	} else {
+		dev_dbg(pmu->dev, "%s: doesn't have clocks: %d\n",
+			node->name, pd->num_clks);
+		pd->num_clks = 0;
+	}
 
 	for (i = 0; i < pd->num_clks; i++) {
 		pd->clks[i].clk = of_clk_get(node, i);