dt-bindings: clock: renesas,r9a09g047-cpg: Add XSPI and GBETH PTP core clocks

dt-bindings: clock: renesas,r9a09g047-cpg: Add XSPI and GBETH PTP core clocks

Add definitions for XSPI core clock and Gigabit Ethernet PTP reference
core clocks in the R9A09G047 CPG DT bindings header file.

The clk_spi is modelled as a fixed divider clock with parent clk_spix2 and
factor two as both parent and child share same gating bit.

Signed-off-by: Biju Das <biju.das.jz@bp.renesas.com>
Acked-by: Krzysztof Kozlowski <krzysztof.kozlowski@linaro.org>
Reviewed-by: Geert Uytterhoeven <geert+renesas@glider.be>
Link: https://lore.kernel.org/20250424081400.135028-2-biju.das.jz@bp.renesas.com
Signed-off-by: Geert Uytterhoeven <geert+renesas@glider.be>