COMPMID-556: Add SoftmaxLayer benchmarks

Change-Id: I1228b1c2bb803666330a4893a374afbd12a52ffb
Reviewed-on: https://eu-gerrit-1.euhpc.arm.com/112107
Tested-by: BSG Visual Compute Jenkins server to access repositories on http://mpd-gerrit.cambridge.arm.com <bsgcomp@arm.com>
Reviewed-by: Anthony Barbier <anthony.barbier@arm.com>
3 files changed