gta4xl-common: rro_overlays: Drop explicit 'sdk_version' declaration

 * We don't need to manually set this anymore.

Change-Id: I1239ba541636e53f8ea4373d3815024f2cd60824
diff --git a/rro_overlays/WifiOverlay/Android.bp b/rro_overlays/WifiOverlay/Android.bp
index c602c22..f345e72 100644
--- a/rro_overlays/WifiOverlay/Android.bp
+++ b/rro_overlays/WifiOverlay/Android.bp
@@ -1,6 +1,5 @@
 runtime_resource_overlay {
     name: "WifiOverlay",
     theme: "WifiOverlay",
-    sdk_version: "current",
     vendor: true
 }