Use apex_available for PermissionController.

Bug: 136503238
Test: build
Change-Id: I8ed378e5eb4ef610d6a919e011e61232e12b504e
diff --git a/apex/apex.go b/apex/apex.go
index 3d1b20e..23dffcb 100644
--- a/apex/apex.go
+++ b/apex/apex.go
@@ -280,10 +280,6 @@
 	//
 	// Module separator
 	//
-	m["com.android.permission"] = []string{"GooglePermissionController", "PermissionController"}
-	//
-	// Module separator
-	//
 	m["com.android.runtime"] = []string{
 		"libbase",
 		"libc++",