Add more CdmResponseType to help with debugging in the field.

The errors in the range ERROR_DRM_VENDOR_MIN to ERROR_DRM_VENDOR_MAX are
reflected in the message that is reported to the app, which is
MediaDrmStateException.getDiagnosticInfo().

Many errors map to kErrorCDMGeneric, especially KEY_ERROR is used as a
generic error in CDM. This fix defines more specific error codes in the
CDM for places where KEY_ERROR is returned.

Merge from http://go/wvgerrit/14071

bug: 19244061
Change-Id: I688bf32828f997000fea041dd29567dde18ac677

libwvdrmengine/cdm/core/src/crypto_session.cpp

@@ -440,7 +440,7 @@ CdmResponseType CryptoSession::LoadKeys(
     return INSUFFICIENT_CRYPTO_RESOURCES;
   } else {
     LOGE("CryptoSession::LoadKeys: OEMCrypto_LoadKeys error=%d", sts);
-    return KEY_ERROR;
+    return LOAD_KEY_ERROR;
   }
 }