r8152: disable the capability of zero length

The UEFI driver would enable zero length, and the Linux driver doesn't
need it. Zero length let the hw complete the transfer with length 0,
when there is no received packet. It would add the load of USB host
controller and reduce the performance.
Signed-off-by: Hayes Wang <hayeswang@realtek.com>
Signed-off-by: David S. Miller <davem@davemloft.net>

drivers/net/usb/r8152.c

@@ -339,6 +339,7 @@
 
 /* USB_USB_CTRL */
 #define RX_AGG_DISABLE		0x0010
+#define RX_ZERO_EN		0x0080
 
 /* USB_U2P3_CTRL */
 #define U2P3_ENABLE		0x0001
@@ -2705,7 +2706,7 @@ static void r8153_first_init(struct r8152 *tp)
 
 	/* rx aggregation */
 	ocp_data = ocp_read_word(tp, MCU_TYPE_USB, USB_USB_CTRL);
-	ocp_data &= ~RX_AGG_DISABLE;
+	ocp_data &= ~(RX_AGG_DISABLE | RX_ZERO_EN);
 	ocp_write_word(tp, MCU_TYPE_USB, USB_USB_CTRL, ocp_data);
 }
 
@@ -3227,7 +3228,7 @@ static void r8152b_init(struct r8152 *tp)
 
 	/* enable rx aggregation */
 	ocp_data = ocp_read_word(tp, MCU_TYPE_USB, USB_USB_CTRL);
-	ocp_data &= ~RX_AGG_DISABLE;
+	ocp_data &= ~(RX_AGG_DISABLE | RX_ZERO_EN);
 	ocp_write_word(tp, MCU_TYPE_USB, USB_USB_CTRL, ocp_data);
 }