clk: tegra: Add interface to enable hardware control of SATA/XUSB PLLs

On Tegra210, hardware control of the SATA and XUSB pad PLLs must be
done during the UPHY enable sequence rather than the PLLE enable
sequence.  Export functions to do this so that hardware control can
be enabled from the XUSB padctl driver.

Signed-off-by: Andrew Bresticker <abrestic@chromium.org>
Signed-off-by: Rhyland Klein <rklein@nvidia.com>
Signed-off-by: Thierry Reding <treding@nvidia.com>