Add tools groups on prebuilts/tools

Change-Id: Iad59091a5cd2f30f326b1b33ff3cd5b5c55ed874
diff --git a/default.xml b/default.xml
index a913e57..7f5b266 100644
--- a/default.xml
+++ b/default.xml
@@ -350,7 +350,7 @@
   <project path="prebuilts/ndk" name="platform/prebuilts/ndk" groups="pdk" />
   <project path="prebuilts/qemu-kernel" name="platform/prebuilts/qemu-kernel" groups="pdk" />
   <project path="prebuilts/sdk" name="platform/prebuilts/sdk" groups="pdk" />
-  <project path="prebuilts/tools" name="platform/prebuilts/tools" groups="pdk" />
+  <project path="prebuilts/tools" name="platform/prebuilts/tools" groups="pdk,tools" />
   <project path="sdk" name="platform/sdk" />
   <project path="system/bluetooth" name="platform/system/bluetooth" groups="pdk" />
   <project path="system/core" name="platform/system/core" groups="pdk" />