MLBEDSW-8219: Activation can not be fused with dma operation

- A reshape followed by an activation function was converted
to a Memcpy with fused activation. The problem is that Memcpy
does not support activation so no activation was executed.

- Added logic to prevent activation functions to be fused
with the Memcpy.

Change-Id: Ibc7d985e5037146dd1f6cb2601407d0f8b865ac6
Signed-off-by: Johan Alfven <johan.alfven@arm.com>