staging: mt7621-mmc: Fix dereference before check in msdc_drv_pm

In the msdc_drv_pm function the variable mmc is dereferenced before
checked. Reordering fixes that.
Reported-by: Dan Carpenter <dan.carpenter@oracle.com>
Signed-off-by: Christian Lütke-Stetzkamp <christian@lkamp.de>
Reviewed-by: NeilBrown <neil@brown.name>
Signed-off-by: Greg Kroah-Hartman <gregkh@linuxfoundation.org>

drivers/staging/mt7621-mmc/sd.c

@@ -2709,10 +2709,10 @@ static int msdc_drv_remove(struct platform_device *pdev)
 static void msdc_drv_pm(struct platform_device *pdev, pm_message state)
 {
 	struct mmc_host *mmc = platform_get_drvdata(pdev);
-	struct msdc_host *host = mmc_priv(mmc);
-
-	if (mmc)
+	if (mmc) {
+		struct msdc_host *host = mmc_priv(mmc);
 		msdc_pm(state, (void *)host);
+	}
 }
 
 static int msdc_drv_suspend(struct platform_device *pdev, pm_message_t state)