board: siemens: iot2050: Stop using special spl DT sources

We can simply use the default DT, Basic PG1, because no nodes that are
different between the variants play a role for SPL. Will help with the
migration to OF_UPSTREAM.

Signed-off-by: Jan Kiszka <jan.kiszka@siemens.com>
diff --git a/arch/arm/dts/k3-am65-iot2050-boot-image.dtsi b/arch/arm/dts/k3-am65-iot2050-boot-image.dtsi
index 3a6db91..e17cd78 100644
--- a/arch/arm/dts/k3-am65-iot2050-boot-image.dtsi
+++ b/arch/arm/dts/k3-am65-iot2050-boot-image.dtsi
@@ -84,12 +84,12 @@
 				};
 
 				fdt-0 {
-					description = "k3-am65-iot2050-spl.dtb";
+					description = "k3-am6528-iot2050-basic.dtb";
 					type = "flat_dt";
 					arch = "arm";
 					compression = "none";
 					blob-ext {
-						filename = "spl/dts/k3-am65-iot2050-spl.dtb";
+						filename = "spl/dts/k3-am6528-iot2050-basic.dtb";
 					};
 				};
 			};