Export bootconfig variables to Soong

Exported variables:
- INTERNAL_BOOTCONFIG
- INTERNAL_BOOTCONFIG_FILE

Test: CI
Bug: 379945468
Change-Id: I0d780a48fa208acd7812d6db5262328319d30fc6
diff --git a/core/soong_config.mk b/core/soong_config.mk
index 4683476..f3d1606 100644
--- a/core/soong_config.mk
+++ b/core/soong_config.mk
@@ -446,6 +446,8 @@
   $(call add_json_str, VendorSecurityPatch, $(VENDOR_SECURITY_PATCH))
   $(call add_json_bool, BoardIncludeDtbInBootimg, $(BOARD_INCLUDE_DTB_IN_BOOTIMG))
   $(call add_json_list, InternalKernelCmdline, $(INTERNAL_KERNEL_CMDLINE))
+  $(call add_json_list, InternalBootconfig, $(INTERNAL_BOOTCONFIG))
+  $(call add_json_str, InternalBootconfigFile, $(INTERNAL_BOOTCONFIG_FILE))
 
   # Avb (android verified boot) stuff
   $(call add_json_bool, BoardAvbEnable, $(filter true,$(BOARD_AVB_ENABLE)))