clk: turn rate change failed warning into pr_debug

If a rate change failed it's the opportunity of the caller to handle
this. Do not spam the log with a message.
Signed-off-by: Sascha Hauer <s.hauer@pengutronix.de>
Cc: linux-arm-kernel@lists.infradead.org
Cc: linux-kernel@vger.kernel.org
Signed-off-by: Mike Turquette <mturquette@linaro.org>

drivers/clk/clk.c

@@ -1591,7 +1591,7 @@ int clk_set_rate(struct clk *clk, unsigned long rate)
 	/* notify that we are about to change rates */
 	fail_clk = clk_propagate_rate_change(top, PRE_RATE_CHANGE);
 	if (fail_clk) {
-		pr_warn("%s: failed to set %s rate\n", __func__,
+		pr_debug("%s: failed to set %s rate\n", __func__,
 				fail_clk->name);
 		clk_propagate_rate_change(top, ABORT_RATE_CHANGE);
 		ret = -EBUSY;