phy: tegra: xusb: Move usb3 port init for Tegra210

The programming sequence in tegra210_usb3_port_enable() is required
for both cold boot and SC7 exit, and must be performed only after
PEX/SATA UPHY is initialized. Therefore, this commit moves the
programming sequence to tegra210_usb3_phy_power_on(). PCIE/SATA phy
.power_on() stub will invoke tegra210_usb3_phy_power_on() if the lane
is assigned for XUSB super-speed.

Signed-off-by: JC Kuo <jckuo@nvidia.com>
Acked-By: Vinod Koul <vkoul@kernel.org>
Signed-off-by: Thierry Reding <treding@nvidia.com>