clk: fixed_rate: add dummy enable() function

This is used to avoid clk_enable() return -ENOSYS.
Signed-off-by: NChunfeng Yun <chunfeng.yun@mediatek.com>
Reviewed-by: NSimon Glass <sjg@chromium.org>
Reviewed-by: NRyder Lee <ryder.lee@mediatek.com>

drivers/clk/clk_fixed_rate.c

@@ -13,8 +13,15 @@ static ulong clk_fixed_rate_get_rate(struct clk *clk)
 	return to_clk_fixed_rate(clk->dev)->fixed_rate;
 }
 
+/* avoid clk_enable() return -ENOSYS */
+static int dummy_enable(struct clk *clk)
+{
+	return 0;
+}
+
 const struct clk_ops clk_fixed_rate_ops = {
 	.get_rate = clk_fixed_rate_get_rate,
+	.enable = dummy_enable,
 };
 
 static int clk_fixed_rate_ofdata_to_platdata(struct udevice *dev)