Widevine drm aidl: address API review

Interface update in change 16810770

Bug: 214410088
Test: atest VtsAidlHalDrmTargetTest
Change-Id: I19da51ef75952f5ff6c7c02e0393f574e69ee30b

libwvdrmengine/aidl_src/WVCreatePluginFactories.cpp

@@ -15,10 +15,6 @@ std::shared_ptr<WVDrmFactory> createDrmFactory() {
   return std::make_shared<WVDrmFactory>();
 }
 
-std::shared_ptr<WVCryptoFactory> createCryptoFactory() {
-  return std::make_shared<WVCryptoFactory>();
-}
-
 }  // namespace widevine
 }  // namespace drm
 }  // namespace hardware