Allocate resources on any incomming RPC operation code

When the Profinet Controller receives a RPC request with an operation code not equal to "Control (4)", it does not allocate RPC request memory and make RPC layer to return status "nca_server_too_busy".

Some RPC client implementation seem to send an RPC Ping with wrong operation code ("0") before sending the actual RPC request. When this Ping is rejected, this implementation don't send the actual request. As a result communication can not be established with such a device.

The controller should accept any incomming operation code during allocation.