phy-sun4i-usb: Change disconnect threshold value for sun6i

The allwinner SDK uses a value of 3 for the disconnect threshold setting on
sun6i, do the same in the kernel.

In my previous experience with sun5i problems getting the threshold right
is important to avoid usb2 devices being unplugged sometimes going unnoticed.

Signed-off-by: Hans de Goede <hdegoede@redhat.com>
Signed-off-by: Kishon Vijay Abraham I <kishon@ti.com>
diff --git a/drivers/phy/phy-sun4i-usb.c b/drivers/phy/phy-sun4i-usb.c
index fb02a67..a2b08f3c 100644
--- a/drivers/phy/phy-sun4i-usb.c
+++ b/drivers/phy/phy-sun4i-usb.c
@@ -244,7 +244,8 @@
 	else
 		data->num_phys = 3;
 
-	if (of_device_is_compatible(np, "allwinner,sun4i-a10-usb-phy"))
+	if (of_device_is_compatible(np, "allwinner,sun4i-a10-usb-phy") ||
+	    of_device_is_compatible(np, "allwinner,sun6i-a31-usb-phy"))
 		data->disc_thresh = 3;
 	else
 		data->disc_thresh = 2;