spi: dw-mmio: Clock should be shut when error occurs

When optional clock requesting fails, the main clock is still up and running,
we should shut it down in such caee.

Fixes: 560ee7e9 ("spi: dw: Add support for an optional interface clock")
Cc: Phil Edworthy <phil.edworthy@renesas.com>
Cc: Gareth Williams <gareth.williams.jx@renesas.com>
Signed-off-by: Andy Shevchenko <andriy.shevchenko@linux.intel.com>
Reviewed-by: Gareth Williams <gareth.williams.jx@renesas.com>
Link: https://lore.kernel.org/r/20190710114243.30101-1-andriy.shevchenko@linux.intel.comSigned-off-by: Mark Brown <broonie@kernel.org>

drivers/spi/spi-dw-mmio.c

@@ -170,8 +170,10 @@ static int dw_spi_mmio_probe(struct platform_device *pdev)
 
 	/* Optional clock needed to access the registers */
 	dwsmmio->pclk = devm_clk_get_optional(&pdev->dev, "pclk");
-	if (IS_ERR(dwsmmio->pclk))
-		return PTR_ERR(dwsmmio->pclk);
+	if (IS_ERR(dwsmmio->pclk)) {
+		ret = PTR_ERR(dwsmmio->pclk);
+		goto out_clk;
+	}
 	ret = clk_prepare_enable(dwsmmio->pclk);
 	if (ret)
 		goto out_clk;