rt2x00usb: initialize the read value in case of failure

My understanding ist that rt2x00usb_register_read() is void and so the
reader is unaware of read errors and assumes that whatever was on the
stack as it was about to read.

Signed-off-by: Sebastian Andrzej Siewior <bigeasy@linutronix.de>
Signed-off-by: Kalle Valo <kvalo@codeaurora.org>

drivers/net/wireless/rt2x00/rt2x00usb.h

@@ -199,7 +199,7 @@ static inline void rt2x00usb_register_read(struct rt2x00_dev *rt2x00dev,
 					   const unsigned int offset,
 					   u32 *value)
 {
-	__le32 reg;
+	__le32 reg = 0;
 	rt2x00usb_vendor_request_buff(rt2x00dev, USB_MULTI_READ,
 				      USB_VENDOR_REQUEST_IN, offset,
 				      &reg, sizeof(reg));
@@ -219,7 +219,7 @@ static inline void rt2x00usb_register_read_lock(struct rt2x00_dev *rt2x00dev,
 						const unsigned int offset,
 						u32 *value)
 {
-	__le32 reg;
+	__le32 reg = 0;
 	rt2x00usb_vendor_req_buff_lock(rt2x00dev, USB_MULTI_READ,
 				       USB_VENDOR_REQUEST_IN, offset,
 				       &reg, sizeof(reg), REGISTER_TIMEOUT);