mmc: sdhci-pxav2: add error handling of clk_prepare_enable()

There is no check if clk_prepare_enable() succeed in sdhci_pxav2_probe().

Found by Linux Driver Verification project (linuxtesting.org).
Signed-off-by: Alexey Khoroshilov <khoroshilov@ispras.ru>
Acked-by: Adrian Hunter <adrian.hunter@intel.com>
Signed-off-by: Ulf Hansson <ulf.hansson@linaro.org>

drivers/mmc/host/sdhci-pxav2.c

@@ -185,7 +185,11 @@ static int sdhci_pxav2_probe(struct platform_device *pdev)
 		goto err_clk_get;
 	}
 	pltfm_host->clk = clk;
-	clk_prepare_enable(clk);
+	ret = clk_prepare_enable(clk);
+	if (ret) {
+		dev_err(&pdev->dev, "failed to enable io clock\n");
+		goto err_clk_enable;
+	}
 
 	host->quirks = SDHCI_QUIRK_BROKEN_ADMA
 		| SDHCI_QUIRK_BROKEN_TIMEOUT_VAL
@@ -228,6 +232,7 @@ static int sdhci_pxav2_probe(struct platform_device *pdev)
 
 err_add_host:
 	clk_disable_unprepare(clk);
+err_clk_enable:
 	clk_put(clk);
 err_clk_get:
 	sdhci_pltfm_free(pdev);