scsi: ufs: fix uninitialized tx_lanes in ufshcd_disable_tx_lcc()

In ufshcd_disable_tx_lcc(), if ufshcd_dme_get() or ufshcd_dme_peer_get()
get fail, uninitialized variable "tx_lanes" may be used as unexpected lane
ID for DME configuration.

Fix this issue by initializing "tx_lanes".

Link: https://lore.kernel.org/r/20200318104016.28049-2-stanley.chu@mediatek.comReviewed-by: Avri Altman <avri.altman@wdc.com>
Reviewed-by: Can Guo <cang@codeaurora.org>
Reviewed-by: Asutosh Das <asutoshd@codeaurora.org>
Signed-off-by: Stanley Chu <stanley.chu@mediatek.com>
Signed-off-by: Martin K. Petersen <martin.petersen@oracle.com>

drivers/scsi/ufs/ufshcd.c

@@ -4249,7 +4249,7 @@ EXPORT_SYMBOL_GPL(ufshcd_hba_enable);
 
 static int ufshcd_disable_tx_lcc(struct ufs_hba *hba, bool peer)
 {
-	int tx_lanes, i, err = 0;
+	int tx_lanes = 0, i, err = 0;
 
 	if (!peer)
 		ufshcd_dme_get(hba, UIC_ARG_MIB(PA_CONNECTEDTXDATALANES),