Add some optional properties for eye diagram test and BC12 of
u2phy
Signed-off-by: Chunfeng Yun <chunfeng.yun@mediatek.com>
Reviewed-by: Rob Herring <robh@kernel.org>
Signed-off-by: Kishon Vijay Abraham I <kishon@ti.com>
                        - PHY_TYPE_PCIE
                        - PHY_TYPE_SATA
 
+Optional properties (PHY_TYPE_USB2 port (child) node):
+- mediatek,eye-src     : u32, the value of slew rate calibrate
+- mediatek,eye-vrt     : u32, the selection of VRT reference voltage
+- mediatek,eye-term    : u32, the selection of HS_TX TERM reference voltage
+- mediatek,bc12        : bool, enable BC12 of u2phy if support it
+
 Example:
 
 u3phy: usb-phy@11290000 {