dt-bindings: clock: starfive: Add JH7100 bindings

Add bindings for the clock generator on the JH7100 RISC-V SoC by
StarFive Ltd. This is a test chip for their upcoming JH7110 SoC.

Reviewed-by: Rob Herring <robh@kernel.org>
Acked-by: Stephen Boyd <sboyd@kernel.org>
Signed-off-by: Geert Uytterhoeven <geert@linux-m68k.org>
Signed-off-by: Emil Renner Berthing <kernel@esmil.dk>