phy: qcom-qmp: pcs-usb: Add v6 register offsets

The new SM8550 SoC bumps up the HW version of QMP phy to v6 for USB.
Add the new PCS USB specific offsets in a dedicated header file.

Signed-off-by: Abel Vesa <abel.vesa@linaro.org>
Link: https://lore.kernel.org/r/20230208183421.2874423-5-abel.vesa@linaro.org
Signed-off-by: Vinod Koul <vkoul@kernel.org>