update exercises

Signed-off-by: Mathieu Desnoyers <mathieu.desnoyers@efficios.com>
Use synchronize_rcu() rather than call_rcu() (more basic example)

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

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

Signed-off-by: Mathieu Desnoyers <mathieu.desnoyers@efficios.com>
update ex2

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