add prebuilts of avbtool and mkdtimg for x15 master builds

Change-Id: Ie09fec0cdfd014548c9ed877fe5f6869b573f266
Signed-off-by: Yongqin Liu <yongqin.liu@linaro.org>
diff --git a/host/bin/avbtool b/host/bin/avbtool
new file mode 100755
index 0000000..715d78a
--- /dev/null
+++ b/host/bin/avbtool
Binary files differ
diff --git a/host/libufdt/PREBUILT b/host/libufdt/PREBUILT
new file mode 100644
index 0000000..9f91190
--- /dev/null
+++ b/host/libufdt/PREBUILT
@@ -0,0 +1,14 @@
+The binary extract_dtb in this prebuilt directory can be rebuilt using
+the source in system/libufdt with build command "make extract_dtb".
+
+The binary mkdtimg in this prebuilt directory can be rebuilt using
+the source in system/libufdt with build command "make mkdtimg".
+
+The binary ufdt_apply_overlay in this prebuilt directory can be rebuilt using
+the source in system/libufdt with build command "make ufdt_apply_overlay_host".
+
+extract_dtb: artifact libufdt/extract_dtb from git_master@3883748 (https://android-build.googleplex.com/builds/submitted/3883748/angler-userdebug_fastbuild3b_linux/latest)
+
+mkdtimg: artifact libufdt/mkdtimg from git_master@5200978 (https://android-build.googleplex.com/builds/submitted/5200978/aosp_marlin-userdebug/latest)
+
+ufdt_apply_overlay: artifact libufdt/ufdt_apply_overlay from git_master@3883748 (https://android-build.googleplex.com/builds/submitted/3883748/angler-userdebug_fastbuild3b_linux/latest)
diff --git a/host/libufdt/extract_dtb b/host/libufdt/extract_dtb
new file mode 100755
index 0000000..df2f40b
--- /dev/null
+++ b/host/libufdt/extract_dtb
Binary files differ
diff --git a/host/libufdt/mkdtimg b/host/libufdt/mkdtimg
new file mode 100755
index 0000000..8cbecae
--- /dev/null
+++ b/host/libufdt/mkdtimg
Binary files differ
diff --git a/host/libufdt/ufdt_apply_overlay b/host/libufdt/ufdt_apply_overlay
new file mode 100755
index 0000000..8e8faba
--- /dev/null
+++ b/host/libufdt/ufdt_apply_overlay
Binary files differ
diff --git a/host/source.txt b/host/source.txt
index 78c1060..1b1d87d 100644
--- a/host/source.txt
+++ b/host/source.txt
@@ -32,3 +32,8 @@
         liblp.so
         libsparse-host.so
         libz-host.so
+avbtool:
+    from the otatools.zip in the following link:
+    https://ci.android.com/builds/submitted/6390383/beagle_x15-userdebug/latest/
+libufdt:
+    from prebuilts/misc repository