void ctl_net_mem_free(void *p);
ctl_net_mem_free frees the object pointed to by p; if p is a null pointer, ctl_net_mem_free does nothing.
ctl_net_mem_free is a wrapper around the free_fn member of the singleton instance of the network memory manager (see CTL_NET_MEM_DRIVER_t).
ctl_net_mem_free should only be used on buffers allocated with ctl_net_mem_alloc_xmit or ctl_net_mem_alloc_data. ctl_net_mem_free is safe to call from an interrupt service routine or the zero-priority main task.