usb: dwc3: add dis_u2_freeclk_exists_quirk

usb: dwc3: add dis_u2_freeclk_exists_quirk

Add a quirk to clear the GUSB2PHYCFG.U2_FREECLK_EXISTS bit,
which specifies whether the USB2.0 PHY provides a free-running
PHY clock, which is active when the clock control input is active.

Refer to commit 27f83eeb6b42("usb: dwc3: add dis_u2_freeclk_exists_quirk")
in Linux Rockchip Kernel.

Signed-off-by: Frank Wang <frank.wang@rock-chips.com>
Reviewed-by: Kever Yang <kever.yang@rock-chips.com>
Reviewed-by: Jagan Teki <jagan@amarulasolutions.com>
Tested-by: Jagan Teki <jagan@amarulasolutions.com>