Revert "Revert "mkbootimg: Build mkbootimg with Soong.""

This reverts commit 55a78bf580.

There's no change in this CL from the initial landing. The earlier crash
was caused by manifest setup in build-tools and clang-tools branches,
which has been addressed by the following CLs.
https://android-review.googlesource.com/c/platform/manifest/+/769045
https://android-review.googlesource.com/c/platform/manifest/+/769044

Bug: 116698229
Change-Id: I33701c9f77e814257cc5c65ad7aa587835ae00ad
Test: TreeHugger

mkbootimg/Android.bp

@@ -31,3 +31,34 @@ cc_library {
     header_libs: ["libmkbootimg_abi_headers"],
     export_header_lib_headers: ["libmkbootimg_abi_headers"],
 }
+
+python_defaults {
+    name: "mkbootimg_defaults",
+
+    version: {
+        py2: {
+            enabled: true,
+            embedded_launcher: true,
+        },
+        py3: {
+            enabled: false,
+            embedded_launcher: false,
+        },
+    },
+}
+
+python_binary_host {
+    name: "mkbootimg",
+    defaults: ["mkbootimg_defaults"],
+    srcs: [
+        "mkbootimg.py",
+    ],
+}
+
+python_binary_host {
+    name: "unpack_bootimg",
+    defaults: ["mkbootimg_defaults"],
+    srcs: [
+        "unpack_bootimg.py",
+    ],
+}

mkbootimg/Android.mk

@@ -1,20 +0,0 @@
-
-LOCAL_PATH:= $(call my-dir)
-include $(CLEAR_VARS)
-
-LOCAL_SRC_FILES := mkbootimg
-LOCAL_MODULE_CLASS := EXECUTABLES
-LOCAL_IS_HOST_MODULE := true
-
-LOCAL_MODULE := mkbootimg
-
-include $(BUILD_PREBUILT)
-
-include $(CLEAR_VARS)
-LOCAL_SRC_FILES := unpack_bootimg
-LOCAL_MODULE_CLASS := EXECUTABLES
-LOCAL_IS_HOST_MODULE := true
-
-LOCAL_MODULE := unpack_bootimg
-
-include $(BUILD_PREBUILT)