phy: qcom-qmp-combo,usb: add support for separate PCS_USB region

Different QMP USB PHYs might have different offset from PCS to PCS_USB
register space, but the same PCS_USB register layout. Add separate
PCS_USB region space and merge related PCS_USB definitions.

Signed-off-by: Dmitry Baryshkov <dmitry.baryshkov@linaro.org>
Link: https://lore.kernel.org/r/20220705094320.1313312-4-dmitry.baryshkov@linaro.org
Signed-off-by: Vinod Koul <vkoul@kernel.org>