Fix Airplay so that it can play music again.

Frontend can be found as an Airplay receiver, but can't play music.
Fix a bug introduced during conversion to std::array (18a6515) to
restore functionality.

mythtv/libs/libmythtv/AirPlay/mythraopconnection.cpp

@@ -616,7 +616,7 @@ uint32_t MythRAOPConnection::decodeAudioPacket(uint8_t type,
     AES_cbc_encrypt((const unsigned char *)data_in,
                     decrypted_data.data(), aeslen,
                     &m_aesKey, iv.data(), AES_DECRYPT);
-    std::copy(data_in + aeslen, data_in + len - aeslen,
+    std::copy(data_in + aeslen, data_in + len,
               decrypted_data.data() + aeslen);
 
     AVPacket tmp_pkt;