Change drm/crypto service names to "default"

bug: 36371166

Test: vts drm hidl test, Play Movies

Change-Id: I942f91ab0be1f237017e88910f8d3738bf54447f
diff --git a/drm/libmediadrm/CryptoHal.cpp b/drm/libmediadrm/CryptoHal.cpp
index 25c16da..d613a5b 100644
--- a/drm/libmediadrm/CryptoHal.cpp
+++ b/drm/libmediadrm/CryptoHal.cpp
@@ -134,7 +134,7 @@
 
     if (factories.size() == 0) {
         // must be in passthrough mode, load the default passthrough service
-        auto passthrough = ICryptoFactory::getService("crypto");
+        auto passthrough = ICryptoFactory::getService();
         if (passthrough != NULL) {
             ALOGI("makeCryptoFactories: using default crypto instance");
             factories.push_back(passthrough);