MLBEDSW-6941: Set correct OFM shape for fc op

If IFM operator shape is rewritten so that batching
is greater than one for fully connect, the OFM batch
must also be calculated. This change will fix output diffs
for networks that have fully connect OFM with rank greater
than 2.

Signed-off-by: Johan Alfven <johan.alfven@arm.com>
Change-Id: I5009edc647a1449a02c8116b45808c1c68beffe6