scripts/Makefile.dts: Rework logic to catch more

Changes from Rasmus Villemoes <rasmus.villemoes@prevas.dk>

Just throwing in a commit here to test.

Signed-off-by: Tom Rini <trini@konsulko.com>
diff --git a/scripts/Makefile.dts b/scripts/Makefile.dts
index 2561025..5e2429c 100644
--- a/scripts/Makefile.dts
+++ b/scripts/Makefile.dts
@@ -1,3 +1,3 @@
 # SPDX-License-Identifier: GPL-2.0+
 
-dtb-y += $(patsubst %,%.dtb,$(subst ",,$(CONFIG_$(SPL_)OF_LIST)))
+dtb-y += $(patsubst %,%.dtb,$(subst ",,$(CONFIG_DEFAULT_DEVICE_TREE) $(CONFIG_OF_LIST) $(CONFIG_SPL_OF_LIST)))