phy: qcom-qmp: split allegedly 4.20 and 5.20 PCS registers

Split registers definitions belonging allegedly to 4.20 and 5.20 QMP
PHYs. They are used for the PCIe QMP PHYs, which have no good open
source reference.

Signed-off-by: Dmitry Baryshkov <dmitry.baryshkov@linaro.org>
Link: https://lore.kernel.org/r/20220705094320.1313312-20-dmitry.baryshkov@linaro.org
Signed-off-by: Vinod Koul <vkoul@kernel.org>