Stop using -Wno-missing-field-initializers

There aren't actually any instances of this warning, so just stop
disabling this warning.

Change-Id: I3e810ab2b478851e0651e71b9fda109be70c3cc7
diff --git a/Android.bp b/Android.bp
index c049e45..c113ed0 100644
--- a/Android.bp
+++ b/Android.bp
@@ -9,7 +9,6 @@
         "-Wall",
         "-Werror",
         "-Wextra",
-        "-Wno-missing-field-initializers",
         "-Wno-unused-parameter",
     ],