Enable arch variant properties in prebuilt_etc.

Bug: 122332178
Test: Soong unit tests + TreeHugger.
Change-Id: Ia8fab0add09478599398e8cbb703debc39f658f6
diff --git a/android/prebuilt_etc.go b/android/prebuilt_etc.go
index 40da653..46d128e 100644
--- a/android/prebuilt_etc.go
+++ b/android/prebuilt_etc.go
@@ -170,7 +170,7 @@
 	module := &PrebuiltEtc{}
 	InitPrebuiltEtcModule(module)
 	// This module is device-only
-	InitAndroidArchModule(module, DeviceSupported, MultilibCommon)
+	InitAndroidArchModule(module, DeviceSupported, MultilibFirst)
 	return module
 }