habanalabs: add debugfs write64/read64

Allow debug user to write/read 64-bit data through debugfs.
This will expedite the dump process of the (large) internal
memories of the device done during debug.

Signed-off-by: Moti Haimovski <mhaimovski@habana.ai>
Reviewed-by: Oded Gabbay <oded.gabbay@gmail.com>
Signed-off-by: Oded Gabbay <oded.gabbay@gmail.com>