PCI: tegra: Program PADS_REFCLK_CFG* always, not just on legacy SoCs

tegra_pcie_phy_power_on() calls tegra_pcie_phy_enable() only for legacy
SoCs.  However, part of tegra_pcie_phy_enable() needs to happen in all
cases.  Move that code up one level into tegra_pcie_phy_power_on().

[bhelgaas: changelog]
Signed-off-by: Stephen Warren <swarren@nvidia.com>
Signed-off-by: Thierry Reding <treding@nvidia.com>
Signed-off-by: Bjorn Helgaas <bhelgaas@google.com>
Reviewed-by: Simon Glass <sjg@chromium.org>