rockchip: rk3399-gru: Sync DT from Linux kernel v6.8

Sync rk3399-gru related device tree from Linux kernel v6.8.

The spi_flash symbol is no longer part of upstream DT, it is re-defined
to allow existing reference use in related u-boot.dtsi-files.

Signed-off-by: Jonas Karlman <jonas@kwiboo.se>
Reviewed-by: Kever Yang <kever.yang@rock-chips.com>
diff --git a/arch/arm/dts/rk3399-gru-u-boot.dtsi b/arch/arm/dts/rk3399-gru-u-boot.dtsi
index 0cc40eb..6bdc892 100644
--- a/arch/arm/dts/rk3399-gru-u-boot.dtsi
+++ b/arch/arm/dts/rk3399-gru-u-boot.dtsi
@@ -78,12 +78,14 @@
 	/delete-property/ bootph-pre-ram;
 };
 
+&spi1 {
+	spi_flash: flash@0 {
+		bootph-all;
+	};
+};
+
 &spi5 {
 	spi-activate-delay = <100>;
 	spi-max-frequency = <3000000>;
 	spi-deactivate-delay = <200>;
 };
-
-&spi_flash {
-	bootph-all;
-};