mmc: wmt-sdmmc: Fix NULL pointer dereference

'of_id' is dereferenced before NULL pointer check. Move it to
after the check.
Signed-off-by: Sachin Kamat <sachin.kamat@linaro.org>
Acked-by: Tony Prisk <linux@prisktech.co.nz>
Signed-off-by: Chris Ball <chris@printf.net>

drivers/mmc/host/wmt-sdmmc.c

@@ -757,7 +757,7 @@ static int wmt_mci_probe(struct platform_device *pdev)
 	struct device_node *np = pdev->dev.of_node;
 	const struct of_device_id *of_id =
 		of_match_device(wmt_mci_dt_ids, &pdev->dev);
-	const struct wmt_mci_caps *wmt_caps = of_id->data;
+	const struct wmt_mci_caps *wmt_caps;
 	int ret;
 	int regular_irq, dma_irq;
 
@@ -766,6 +766,8 @@ static int wmt_mci_probe(struct platform_device *pdev)
 		return -EFAULT;
 	}
 
+	wmt_caps = of_id->data;
+
 	if (!np) {
 		dev_err(&pdev->dev, "Missing SDMMC description in devicetree\n");
 		return -EFAULT;