libhwminijail from hardware/interfaces to libhidl.

This library is not a hardware interface, so it doesn't
belong directly in hardware/interfaces. Moving it to
libhidl because it is intended to be a helper library for
hal implementations that want to use minijail/seccomp.

Test: pass
Change-Id: Id435c70ef9483006e09896be81d5f9600b758e47
diff --git a/Android.bp b/Android.bp
index 962984c..e97c28c 100644
--- a/Android.bp
+++ b/Android.bp
@@ -16,6 +16,7 @@
     "adapter",
     "base",           // libhidlbase
     "libhidlmemory",  // libhidlmemory
+    "minijail",
     "transport",      // libhidltransport
 ]