i2c: efm32: fix a failure path in efm32_i2c_probe()

There is the only failure path in efm32_i2c_probe(),
where clk_disable_unprepare() is missed.

Found by Linux Driver Verification project (linuxtesting.org).
Signed-off-by: Alexey Khoroshilov <khoroshilov@ispras.ru>
Acked-by: Uwe Kleine-König <u.kleine-koenig@pengutronix.de>
Signed-off-by: Wolfram Sang <wsa@the-dreams.de>
Fixes: 1b5b2371 ("i2c: efm32: new bus driver")
Cc: stable@kernel.org

drivers/i2c/busses/i2c-efm32.c

@@ -433,7 +433,7 @@ static int efm32_i2c_probe(struct platform_device *pdev)
 	ret = request_irq(ddata->irq, efm32_i2c_irq, 0, DRIVER_NAME, ddata);
 	if (ret < 0) {
 		dev_err(&pdev->dev, "failed to request irq (%d)\n", ret);
-		return ret;
+		goto err_disable_clk;
 	}
 
 	ret = i2c_add_adapter(&ddata->adapter);