dt-bindings: clock: r8a779a0: Add ZG core clock

Add the core clock used by the GPU on the Renesas R-Car V3U
(R8A779A0) SoC.

Signed-off-by: Niklas Söderlund <niklas.soderlund+renesas@ragnatech.se>
Acked-by: Krzysztof Kozlowski <krzysztof.kozlowski@linaro.org>
Reviewed-by: Geert Uytterhoeven <geert+renesas@glider.be>
Link: https://patch.msgid.link/20251106211604.2766465-2-niklas.soderlund+renesas@ragnatech.se
Signed-off-by: Geert Uytterhoeven <geert+renesas@glider.be>

Author: Niklas Söderlund

include/dt-bindings/clock/r8a779a0-cpg-mssr.h

@@ -51,5 +51,6 @@
 #define R8A779A0_CLK_CBFUSA		40
 #define R8A779A0_CLK_R			41
 #define R8A779A0_CLK_OSC		42
+#define R8A779A0_CLK_ZG			43
 
 #endif /* __DT_BINDINGS_CLOCK_R8A779A0_CPG_MSSR_H__ */