The function for logging RMI calls specifies the wrong number of output args

[soby-mathew]

The RMI handlers are registered using this data structure here: https://github.com/TF-RMM/tf-rmm/blob/rmm-spec-v1.0-eac2/runtime/core/handler.c#L127

The number of output arguments do not correlate to the actual handlers. These need to be corrected so the logs are output correctly.

[soby-mathew]

The implementation is correct. The number of output args in the handler structure does not count the default return argument via x0.