clk: rockchip: rk3308: Add dummy support for USB480M clock

Add dummy support for setting parent of USB480M clock.

Signed-off-by: Jonas Karlman <jonas@kwiboo.se>
Reviewed-by: Kever Yang <kever.yang@rock-chips.com>
diff --git a/drivers/clk/rockchip/clk_rk3308.c b/drivers/clk/rockchip/clk_rk3308.c
index 7515fc8..c46b58e 100644
--- a/drivers/clk/rockchip/clk_rk3308.c
+++ b/drivers/clk/rockchip/clk_rk3308.c
@@ -1085,6 +1085,8 @@
 	case SCLK_RTC32K:
 		ret = rk3308_rtc32k_set_clk(priv, clk->id, rate);
 		break;
+	case USB480M:
+		return 0;
 	default:
 		return -ENOENT;
 	}
@@ -1117,6 +1119,8 @@
 	switch (clk->id) {
 	case SCLK_MAC:
 		return rk3308_mac_set_parent(clk, parent);
+	case USB480M:
+		return 0;
 	default:
 		break;
 	}