phy: qcom-qmp-pcie: add support for pipediv2 clock

Some QMP PHYs have a second fixed-divider pipe clock that needs to be
enabled along with the pipe clock.

Add support for an optional "pipediv2" clock.

Reviewed-by: Dmitry Baryshkov <dmitry.baryshkov@linaro.org>
Signed-off-by: Johan Hovold <johan+linaro@kernel.org>
Link: https://lore.kernel.org/r/20221105145939.20318-15-johan+linaro@kernel.org
Signed-off-by: Vinod Koul <vkoul@kernel.org>