Migrate tracepoint instrumentation to TP_FIELDS

At this stage syscall instrumentation is disabled. Will come in a
following commit.

Signed-off-by: Mathieu Desnoyers <mathieu.desnoyers@efficios.com>
Migrate syscall instrumentation to TP_FIELDS

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