serial: mxs-auart: Fix missing clk_disable_unprepare() on error in mxs_get_clks()

Commit 5d7519df ("serial: mxs-auart: Disable clock on error path")
try to disable clock on error path, but still missing the clk_set_rate()
error handling path.
Signed-off-by: Wei Yongjun <weiyongjun1@huawei.com>
Reviewed-by: Fabio Estevam <fabio.estevam@nxp.com>
Signed-off-by: Greg Kroah-Hartman <gregkh@linuxfoundation.org>

drivers/tty/serial/mxs-auart.c

@@ -1534,7 +1534,7 @@ static int mxs_get_clks(struct mxs_auart_port *s,
 	err = clk_set_rate(s->clk, clk_get_rate(s->clk_ahb));
 	if (err) {
 		dev_err(s->dev, "Failed to set rate!\n");
-		return err;
+		goto disable_clk_ahb;
 	}
 
 	err = clk_prepare_enable(s->clk);