scsi: ufs: ufshcd: fix potential NULL pointer dereference in ufshcd_config_vreg

_vreg_ is being dereferenced before it is null checked, hence there is a
potential null pointer dereference.

Fix this by moving the pointer dereference after _vreg_ has been null
checked.

This issue was detected with the help of Coccinelle.

Fixes: aa497613 ("ufs: Add regulator enable support")
Signed-off-by: Gustavo A. R. Silva <garsilva@embeddedor.com>
Reviewed-by: Subhash Jadavani <subhashj@codeaurora.org>
Signed-off-by: Martin K. Petersen <martin.petersen@oracle.com>

drivers/scsi/ufs/ufshcd.c

@@ -6559,12 +6559,15 @@ static int ufshcd_config_vreg(struct device *dev,
 		struct ufs_vreg *vreg, bool on)
 {
 	int ret = 0;
-	struct regulator *reg = vreg->reg;
-	const char *name = vreg->name;
+	struct regulator *reg;
+	const char *name;
 	int min_uV, uA_load;
 
 	BUG_ON(!vreg);
 
+	reg = vreg->reg;
+	name = vreg->name;
+
 	if (regulator_count_voltages(reg) > 0) {
 		min_uV = on ? vreg->min_uV : 0;
 		ret = regulator_set_voltage(reg, min_uV, vreg->max_uV);