clk: add support for TI K3 SoC PLL

Add support for TI K3 SoC PLLs. This clock type supports
enabling/disabling/setting and querying the clock rate for the PLL. The
euclidean library routine is used to calculate divider/multiplier rates
for the PLLs.

Signed-off-by: Tero Kristo <t-kristo@ti.com>
Signed-off-by: Tero Kristo <kristo@kernel.org>