clk: rockchip: use match_string() helper

match_string() returns the index of an array for a matching string,
which can be used intead of open coded variant.

Cc: Michael Turquette <mturquette@baylibre.com>
Cc: Stephen Boyd <sboyd@kernel.org>
Cc: Heiko Stuebner <heiko@sntech.de>
Cc: linux-clk@vger.kernel.org
Cc: linux-arm-kernel@lists.infradead.org
Cc: linux-rockchip@lists.infradead.org
Signed-off-by: Yisheng Xie <xieyisheng1@huawei.com>
Signed-off-by: Heiko Stuebner <heiko@sntech.de>

drivers/clk/rockchip/clk.c

@@ -274,18 +274,10 @@ static struct clk *rockchip_clk_register_frac_branch(
 		struct clk_mux *frac_mux = &frac->mux;
 		struct clk_init_data init;
 		struct clk *mux_clk;
-		int i, ret;
-
-		frac->mux_frac_idx = -1;
-		for (i = 0; i < child->num_parents; i++) {
-			if (!strcmp(name, child->parent_names[i])) {
-				pr_debug("%s: found fractional parent in mux at pos %d\n",
-					 __func__, i);
-				frac->mux_frac_idx = i;
-				break;
-			}
-		}
+		int ret;
 
+		frac->mux_frac_idx = match_string(child->parent_names,
+						  child->num_parents, name);
 		frac->mux_ops = &clk_mux_ops;
 		frac->clk_nb.notifier_call = rockchip_clk_frac_notifier_cb;
 
@@ -312,6 +304,8 @@ static struct clk *rockchip_clk_register_frac_branch(
 
 		/* notifier on the fraction divider to catch rate changes */
 		if (frac->mux_frac_idx >= 0) {
+			pr_debug("%s: found fractional parent in mux at pos %d\n",
+				 __func__, frac->mux_frac_idx);
 			ret = clk_notifier_register(clk, &frac->clk_nb);
 			if (ret)
 				pr_err("%s: failed to register clock notifier for %s\n",