Create Broadcast radio HAL 1.1; implement DigitalStatus enum.

Test: VTS
Change-Id: I338c467c4e373cae547f331ba876afa040238376
diff --git a/broadcastradio/1.1/WARNING b/broadcastradio/1.1/WARNING
new file mode 100644
index 0000000..e867cfa
--- /dev/null
+++ b/broadcastradio/1.1/WARNING
@@ -0,0 +1 @@
+This is experimental interface, do not use it yet.