Build cpu_features for Windows too.

Since upstream supports it...

(Not necessarily needed, but Studio might be interested in using
cpu_features, and they'll want Windows.)

Test: builds
Change-Id: I8e0f9cbc4d9ce7bb6db3574946731b4d7e636290
diff --git a/Android.bp b/Android.bp
index ea14659..c7569de 100644
--- a/Android.bp
+++ b/Android.bp
@@ -22,6 +22,11 @@
         "src/stack_line_reader.c",
         "src/string_view.c",
     ],
+    target: {
+        windows: {
+            enabled: true,
+        },
+    },
 }
 
 cc_library {
@@ -92,6 +97,11 @@
             ],
         },
     },
+    target: {
+        windows: {
+            enabled: true,
+        },
+    },
 }
 
 cc_binary {