r8152: fix the checking of the usb speed

When the usb speed of the RTL8152 is not high speed, the USB_DEV_STAT[2:1]
should be equal to [0 1]. That is, the STAT_SPEED_FULL should be equal
to 2.

There is a easy way to check the usb speed by the speed field of the
struct usb_device. Use it to replace the original metheod.
Signed-off-by: Hayes Wang <hayeswang@realtek.com>
Spotted-by: Andrey Utkin <andrey.krieger.utkin@gmail.com>
Signed-off-by: David S. Miller <davem@davemloft.net>

drivers/net/usb/r8152.c

@@ -282,7 +282,7 @@
 /* USB_DEV_STAT */
 #define STAT_SPEED_MASK		0x0006
 #define STAT_SPEED_HIGH		0x0000
-#define STAT_SPEED_FULL		0x0001
+#define STAT_SPEED_FULL		0x0002
 
 /* USB_TX_AGG */
 #define TX_AGG_MAX_THRESHOLD	0x03
@@ -2292,9 +2292,8 @@ static void r8152b_exit_oob(struct r8152 *tp)
 	/* rx share fifo credit full threshold */
 	ocp_write_dword(tp, MCU_TYPE_PLA, PLA_RXFIFO_CTRL0, RXFIFO_THR1_NORMAL);
 
-	ocp_data = ocp_read_word(tp, MCU_TYPE_USB, USB_DEV_STAT);
-	ocp_data &= STAT_SPEED_MASK;
-	if (ocp_data == STAT_SPEED_FULL) {
+	if (tp->udev->speed == USB_SPEED_FULL ||
+	    tp->udev->speed == USB_SPEED_LOW) {
 		/* rx share fifo credit near full threshold */
 		ocp_write_dword(tp, MCU_TYPE_PLA, PLA_RXFIFO_CTRL1,
 				RXFIFO_THR2_FULL);