MLBEDSW-8927 Add Ethos-U55/U65 support for MIRROR_PAD in Regor

* Updated the regor Ethos-U55/U65 backend to handle OFM reverse in H and W axes.
* Added architectural constraints for negative striding in order to
force linear format for OFM reversals for Ethos-U55/U65.
* Minor print-formatting change to high_level_command_stream.py.

Change-Id: I30b97b8c7fadf5306ca960bd4b45087513270864
Signed-off-by: Jacob Bohlin <jacob.bohlin@arm.com>