phy: qcom-qmp: split allegedly 4.20 and 5.20 TX/RX 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/20220705094320.1313312-19-dmitry.baryshkov@linaro.org
Signed-off-by: Vinod Koul <vkoul@kernel.org>