Make bzip2 available for the host too.

(bzip2 is currently in the `Allowed` list in `ui/build/paths/config.go`.)

Test: builds
Change-Id: I80ac17661f76e91de86556e9c67287b150082106
diff --git a/Android.bp b/Android.bp
index 8092f56..a2023e7 100644
--- a/Android.bp
+++ b/Android.bp
@@ -45,13 +45,15 @@
 
 cc_binary {
     name: "bzip2",
-    srcs: ["bzip2.c"],
-    shared_libs: ["libbz"],
-    stl: "none",
+    host_supported: true,
+
     cflags: [
         "-Werror",
         "-Wno-unused-parameter",
     ],
+    shared_libs: ["libbz"],
+    srcs: ["bzip2.c"],
+    stl: "none",
     symlinks: [
         "bunzip2",
         "bzcat",