There are several SoCs (e.g. rk3228h and rk3328) that integrated
with Inno USB3 PHY, they can't toggle CP test pattern when do
USB3 compliance test by default.
This patch add a cp_test callback for USB3 controller to enable
the special USB3 PHY to toggle the CP test pattern.
Change-Id: I2d603202723a4c044d4231af10cfe2c60ec0e988
Signed-off-by: William Wu <wulf@rock-chips.com>