dt-bindings: clock: Convert ti,sci-clk to json schema

Convert the ti,sci-clk to json schema for better checks and documentation.

Differences being:
 - Drop consumer example as they are documented in the corresponding
   bindings themselves.
 - Standardize the node name as clock-controller rather than clocks as
   it is more appropriate.
 - Drop phandle description for clock-cells as it is redundant.

Signed-off-by: Nishanth Menon <nm@ti.com>
Reviewed-by: Tero Kristo <kristo@kernel.org>
Acked-by: Stephen Boyd <sboyd@kernel.org>
Link: https://lore.kernel.org/r/20210426155457.21221-3-nm@ti.com


Signed-off-by: Rob Herring <robh@kernel.org>