Adding adb_debug.prop into debug ramdisk

The debug ramdisk can only be used if the device is unlocked.
When it's used, init will load adb_debug.prop and the userdebug
sepolicy from the debug ramdisk, to allow adb root on a user build.

Bug: 126493225
Test: 'make' and checks the file is installed
Change-Id: Id6962414197fc8f47f7c07818e8fb16107dc17a3
Merged-In: Id6962414197fc8f47f7c07818e8fb16107dc17a3
(cherry picked from commit 05f07d89a6b44eef1fcec020bf9020a3429fc3ad)
diff --git a/rootdir/Android.mk b/rootdir/Android.mk
index a97858a..7ff1588 100644
--- a/rootdir/Android.mk
+++ b/rootdir/Android.mk
@@ -377,4 +377,13 @@
 	$(hide) $(foreach lib,$(PRIVATE_VNDK_SAMEPROCESS_LIBRARIES), \
 		echo $(lib).so >> $@;)
 
+#######################################
+# adb_debug.prop in debug ramdisk
+include $(CLEAR_VARS)
+LOCAL_MODULE := adb_debug.prop
+LOCAL_SRC_FILES := $(LOCAL_MODULE)
+LOCAL_MODULE_CLASS := ETC
+LOCAL_MODULE_PATH := $(TARGET_DEBUG_RAMDISK_OUT)
+include $(BUILD_PREBUILT)
+
 include $(call all-makefiles-under,$(LOCAL_PATH))