arm: dts: iot2050: Include u-boot specific bits implicitly

Create *-u-boot.dtsi files for each target dtb of the IOT2050 series so
that we can drop the #include deviations from upstream dts[i] files
here.

Signed-off-by: Jan Kiszka <jan.kiszka@siemens.com>
diff --git a/arch/arm/dts/k3-am6528-iot2050-basic-pg2-u-boot.dtsi b/arch/arm/dts/k3-am6528-iot2050-basic-pg2-u-boot.dtsi
new file mode 100644
index 0000000..1e39304
--- /dev/null
+++ b/arch/arm/dts/k3-am6528-iot2050-basic-pg2-u-boot.dtsi
@@ -0,0 +1,11 @@
+// SPDX-License-Identifier: GPL-2.0
+/*
+ * Copyright (c) Siemens AG, 2023
+ *
+ * Authors:
+ *   Jan Kiszka <jan.kiszka@siemens.com>
+ */
+
+#include "k3-am65-iot2050-common-u-boot.dtsi"
+#include "k3-am65-iot2050-common-pg2-u-boot.dtsi"
+#include "k3-am65-iot2050-boot-image.dtsi"