scsi: ufs: don't check unsigned type for a negative value

Fix compilation warning:

drivers/scsi/ufs/ufshcd.c:7645:13: warning: comparison of unsigned
expression < 0 is always false [-Wtype-limits]
if ((value < UFS_PM_LVL_0) || (value >= UFS_PM_LVL_MAX))
Signed-off-by: Tomas Winkler <tomas.winkler@intel.com>
Reviewed-by: Subhash Jadavani <subhashj@codeaurora.org>
Signed-off-by: Martin K. Petersen <martin.petersen@oracle.com>

drivers/scsi/ufs/ufshcd.c

@@ -7642,7 +7642,7 @@ static inline ssize_t ufshcd_pm_lvl_store(struct device *dev,
 	if (kstrtoul(buf, 0, &value))
 		return -EINVAL;
 
-	if ((value < UFS_PM_LVL_0) || (value >= UFS_PM_LVL_MAX))
+	if (value >= UFS_PM_LVL_MAX)
 		return -EINVAL;
 
 	spin_lock_irqsave(hba->host->host_lock, flags);