aiaiai: use fail_usage on incorrect number of arguments

aiaiai: use fail_usage on incorrect number of arguments

We should display the full usage with an error message when we have an
incorrect number of arguments, rather than just die. The advantage is
that the user will see what the actual usage of the program is, rather
than just a somewhat cryptic error message.

Signed-off-by: Jacob Keller <jacob.e.keller@intel.com>
Signed-off-by: Artem Bityutskiy <artem.bityutskiy@linux.intel.com>