arm64: dts: rockchip: correct usb-controler reference clk for rk3366

arm64: dts: rockchip: correct usb-controler reference clk for rk3366

We found that the system on rk3366-sdk will crash at the first time
after updating the whole firmware, the root cause is the 480m clock
from usb-phy has some issues.

Since the new usb-phy driver have taken over the 480m clock's
maintenance, the clock tree have a bit changes, so related
reference clock for usb-controler also need to correct.

Change-Id: I54dcc6f416adf61c34df2b9b897e5b58f3b6fed8
Signed-off-by: Frank Wang <frank.wang@rock-chips.com>