client: use heap to store mgcp_response

The struct that holds the parsing results of the MGCP response is
allocated on the stack. However, it would make sense to allocate
the struct dynamically on the heap. This also would provide a
talloc context that is in reach on most places of the code.

- Allocate struct mgcp_response dynamically in mgcp_client_rx()

- Use struct mgcp_response as talloc context for temporary
  allocated memory while parsing the response.

Change-Id: I5099abe68b580c75b47bc797bf93f01084f0c4db
1 file changed