The defaults listed in the bindings don't match what the code is
actually doing.  Presumably existing users care more about keeping
existing behavior the same, so change the bindings to match the code
in Linux.

The "qcom,preemphasis-level" default has been wrong for quite a long
time (May 2018).  The other two were recently added.

As some evidence that these values are wrong, this is from the Linux
driver:
- qcom,preemphasis-level: sets "PORT_TUNE1", lower 2 bits.  Driver
  programs PORT_TUNE1 to 0x30 by default and (0x30 & 0x3) = 0.
- qcom,bias-ctrl-value: sets "PLL_BIAS_CONTROL_2", lower 6 bits.
  Driver programs PLL_BIAS_CONTROL_2 to 0x20 by default and (0x20 &
  0x3f) = 0x20 = 32.
- qcom,hsdisc-trim-value: sets "PORT_TUNE2", lower 2 bits.  Driver
  programs PORT_TUNE2 to 0x29 by default and (0x29 & 0x3) = 1.

Fixes: 1e6f134e ("dt-bindings: phy: qcom-qusb2: Add support for overriding Phy tuning parameters")
Fixes: a8b70ccf ("dt-bindings: phy-qcom-usb2: Add support to override tuning values")
Signed-off-by: Douglas Anderson <dianders@chromium.org>
Reviewed-by: Matthias Kaehlcke <mka@chromium.org>
Signed-off-by: Rob Herring <robh@kernel.org>