phy: qcom-qmp-pcie: clean up PHY lane init

Clean up the PHY lane initialisation somewhat by adding further
temporary variables and programming both tx and rx for the second lane
after the first lane.

Reviewed-by: Dmitry Baryshkov <dmitry.baryshkov@linaro.org>
Signed-off-by: Johan Hovold <johan+linaro@kernel.org>