Export BOARD_INCLUDE_DTB_IN_BOOTIMG to Soong

Test: CI
Bug: 379945468
Change-Id: I7c066170243055df9f9eefc5ab337dadc3701883
diff --git a/core/soong_config.mk b/core/soong_config.mk
index c9c6e4a..bf65206 100644
--- a/core/soong_config.mk
+++ b/core/soong_config.mk
@@ -444,6 +444,7 @@
   $(call add_json_str, BootSecurityPatch, $(BOOT_SECURITY_PATCH))
   $(call add_json_str, InitBootSecurityPatch, $(INIT_BOOT_SECURITY_PATCH))
   $(call add_json_str, VendorSecurityPatch, $(VENDOR_SECURITY_PATCH))
+  $(call add_json_bool, BoardIncludeDtbInBootimg, $(BOARD_INCLUDE_DTB_IN_BOOTIMG))
 
   # Avb (android verified boot) stuff
   $(call add_json_bool, BoardAvbEnable, $(filter true,$(BOARD_AVB_ENABLE)))