phy: qcom-qmp: qserdes-txrx: Add v6.20 register offsets

The new SM8550 SoC bumps up the HW version of QMP phy to v6.20 for
PCIE g4x2. Add the new qserdes TX RX PCIE specific offsets in a
dedicated header file.

Signed-off-by: Abel Vesa <abel.vesa@linaro.org>
Reviewed-by: Dmitry Baryshkov <dmitry.baryshkov@linaro.org>
Link: https://lore.kernel.org/r/20230208180020.2761766-7-abel.vesa@linaro.org
Signed-off-by: Vinod Koul <vkoul@kernel.org>