ARM: dts: uniphier: include System Bus pin group node in SPL DT

This will be needed for setting up the System Bus pin-mux via the
LD11/LD20 pinctrl driver.

Signed-off-by: Masahiro Yamada <yamada.masahiro@socionext.com>
diff --git a/arch/arm/dts/uniphier-ph1-ld11-ref.dts b/arch/arm/dts/uniphier-ph1-ld11-ref.dts
index 4eb7664..ca31026 100644
--- a/arch/arm/dts/uniphier-ph1-ld11-ref.dts
+++ b/arch/arm/dts/uniphier-ph1-ld11-ref.dts
@@ -70,3 +70,7 @@
 &pinctrl_uart0 {
 	u-boot,dm-pre-reloc;
 };
+
+&pinctrl_system_bus {
+	u-boot,dm-pre-reloc;
+};