arm64: dts: h3ulcb: enable EXTALR clk

This enables EXTALR clock that can be used for the watchdog.
Signed-off-by: NVladimir Barinov <vladimir.barinov@cogentembedded.com>
Reviewed-by: NGeert Uytterhoeven <geert+renesas@glider.be>
Signed-off-by: NSimon Horman <horms+renesas@verge.net.au>

arch/arm64/boot/dts/renesas/r8a7795-h3ulcb.dts

@@ -37,6 +37,10 @@
 	clock-frequency = <16666666>;
 };
 
+&extalr_clk {
+	clock-frequency = <32768>;
+};
+
 &pfc {
 	pinctrl-0 = <&scif_clk_pins>;
 	pinctrl-names = "default";