clk: tegra: Add fixed factor peripheral clock type

Some of the peripheral clocks on Tegra are derived from one of the top-
level PLLs with a fixed factor. Support these clocks by implementing the
->enable() and ->disable() callbacks using the peripheral clock register
banks and the ->recalc_rate() by dividing the parent rate by the fixed
factor.

Signed-off-by: Thierry Reding <treding@nvidia.com>