Make required a configurable property

So that users can use select statements with it.

Fixes: 347605145
Bug: 342006386
Test: m nothing --no-skip-soong-tests
Change-Id: Ica0ca6d1725b000b3748c0293e5a9f9b38ed87f9
diff --git a/apex/androidmk.go b/apex/androidmk.go
index 619be8d..4112108 100644
--- a/apex/androidmk.go
+++ b/apex/androidmk.go
@@ -218,7 +218,7 @@
 	var required []string
 	var targetRequired []string
 	var hostRequired []string
-	required = append(required, a.RequiredModuleNames()...)
+	required = append(required, a.required...)
 	targetRequired = append(targetRequired, a.TargetRequiredModuleNames()...)
 	hostRequired = append(hostRequired, a.HostRequiredModuleNames()...)
 	for _, fi := range a.filesInfo {