COMPMID-417 - Fix graph_letnet.cpp example

In case the library has been built just for NEON, we should not run the example

Change-Id: I99f8d3efd20276dfeb73ca8362872111be1b1fd7
Reviewed-on: http://mpd-gerrit.cambridge.arm.com/89682
Reviewed-by: Anthony Barbier <anthony.barbier@arm.com>
Tested-by: Kaizen <jeremy.johnson+kaizengerrit@arm.com>
1 file changed