DeviceUsesClang should default to true

It defaults to true in Make now.

Change-Id: Id216c35d4a4fc87ce19067a357561a7fc814cbbb
diff --git a/common/config.go b/common/config.go
index 6fd6dfc..ef59cf7 100644
--- a/common/config.go
+++ b/common/config.go
@@ -261,7 +261,7 @@
 	if c.ProductVariables.DeviceUsesClang != nil {
 		return *c.ProductVariables.DeviceUsesClang
 	}
-	return false
+	return true
 }
 
 func (c *config) ResourceOverlays() []SourcePath {