Add system/tools/aidl to manifest

Test: repo sync'd this path just fine.
Bug: 23691099

default.xml

@@ -511,6 +511,7 @@
   <project path="system/netd" name="platform/system/netd" groups="pdk" />
   <project path="system/peerd" name="platform/system/peerd" />
   <project path="system/security" name="platform/system/security" groups="pdk" />
+  <project path="system/tools/aidl" name="platform/system/tools/aidl" groups="pdk-cw-fs,pdk-fs" />
   <project path="system/tpm_manager" name="platform/system/tpm_manager" />
   <project path="system/trunks" name="platform/system/trunks" />
   <project path="system/update_engine" name="platform/system/update_engine" />