phy: rockchip: usbdp: optimize the power on flow

when we set mode change flag and the phy is idle, here
will not clear the mode change flag when power on, we
need clear it.

Signed-off-by: Zhang Yubing <yubing.zhang@rock-chips.com>
Change-Id: I900d5c37a2e83212eb6461d714a653c93da923c7

drivers/phy/rockchip/phy-rockchip-usbdp.c

@@ -689,6 +689,7 @@ static int udphy_power_on(struct rockchip_udphy *udphy, u8 mode)
 	}
 
 	if (udphy->status == UDPHY_MODE_NONE) {
+		udphy->mode_change = false;
 		ret = udphy_setup(udphy);
 		if (ret)
 			return ret;