ASoC: rockchip: i2s: Fix missing error code in rockchip_i2s_probe()

The error code is missing in this code scenario, add the error code
'-EINVAL' to the return value 'ret'.

This was found by coccicheck:

sound/soc/rockchip/rockchip_i2s.c:810 rockchip_i2s_probe() warn: missing error code 'ret'.
Signed-off-by: Jiapeng Chong <jiapeng.chong@linux.alibaba.com>
Link: https://lore.kernel.org/r/20220624082745.68367-1-jiapeng.chong@linux.alibaba.comSigned-off-by: Mark Brown <broonie@kernel.org>

sound/soc/rockchip/rockchip_i2s.c

@@ -807,6 +807,7 @@ static int rockchip_i2s_probe(struct platform_device *pdev)
 			i2s->bclk_off = pinctrl_lookup_state(i2s->pinctrl, "bclk_off");
 			if (IS_ERR_OR_NULL(i2s->bclk_off)) {
 				dev_err(&pdev->dev, "failed to find i2s bclk_off\n");
+				ret = -EINVAL;
 				goto err_clk;
 			}
 		}