accel/habanalabs: fix debugfs files permissions

debugfs files are created with permissions that don't align
with the access requirements.

Signed-off-by: Avri Kehat <akehat@habana.ai>
Reviewed-by: Oded Gabbay <ogabbay@kernel.org>
Reviewed-by: Carl Vanderlip <quic_carlv@quicinc.com>
Signed-off-by: Oded Gabbay <ogabbay@kernel.org>