COMPMID-417: Fix negative overflowing in NESoftmaxLayer.

Change-Id: Ic8fa05ac44855f591ae8f5de63204973f5694c83
Reviewed-on: http://mpd-gerrit.cambridge.arm.com/78880
Tested-by: Kaizen <jeremy.johnson+kaizengerrit@arm.com>
Reviewed-by: Anthony Barbier <anthony.barbier@arm.com>
1 file changed