Rename LTTng syscall instrumentation macros

Mapping:

SC_LTTNG_TRACE_EVENT -> SC_LTTNG_TRACEPOINT_EVENT_CODE
SC_TRACE_EVENT -> SC_LTTNG_TRACEPOINT_EVENT
SC_DECLARE_EVENT_CLASS_NOARGS -> SC_LTTNG_TRACEPOINT_EVENT_CLASS_NOARGS
SC_DEFINE_EVENT_NOARGS -> SC_LTTNG_TRACEPOINT_EVENT_INSTANCE_NOARGS

Signed-off-by: Mathieu Desnoyers <mathieu.desnoyers@efficios.com>