Correct AES bit size for generic crypto

Merge from Widevine repo of http://go/wvgerrit/42402

This changes the AES key size back to 128 for keys that are not
entitlment keys.

bug: 72904259
test: unit tests
Change-Id: I07cc56050cafb82c65b67c56df3f18d375047eb8

libwvdrmengine/oemcrypto/mock/src/oemcrypto_session.h

@@ -189,7 +189,8 @@ class SessionContext {
   bool DecryptMessage(const std::vector<uint8_t>& key,
                       const std::vector<uint8_t>& iv,
                       const std::vector<uint8_t>& message,
-                      std::vector<uint8_t>* decrypted);
+                      std::vector<uint8_t>* decrypted,
+                      uint32_t key_size);  // AES key size, in bits.
   // Either verify the nonce or usage entry, as required by the key control
   // block.
   OEMCryptoResult CheckNonceOrEntry(const KeyControlBlock& key_control_block);