arm64: dts: renesas: r9a09g056n48-rzv2n-evk: Add alias for on-SoC RTC

The RZ/V2N SoC provides an internal RTC, which is enabled in the DT.
The RZ/V2N EVK board also includes an external RTC in the RAA215300
PMIC.

Add an "rtc0" alias pointing to the on-SoC RTC node to ensure a stable
device numbering.

Signed-off-by: Lad Prabhakar <prabhakar.mahadev-lad.rj@bp.renesas.com>
Reviewed-by: Geert Uytterhoeven <geert+renesas@glider.be>
Link: https://patch.msgid.link/20260506155804.3984418-3-prabhakar.mahadev-lad.rj@bp.renesas.com
Signed-off-by: Geert Uytterhoeven <geert+renesas@glider.be>

Author: prabhakarlad

arch/arm64/boot/dts/renesas/r9a09g056n48-rzv2n-evk.dts

@@ -26,6 +26,7 @@
 		i2c7 = &i2c7;
 		i2c8 = &i2c8;
 		mmc1 = &sdhi1;
+		rtc0 = &rtc;
 		serial0 = &scif;
 	};