habanalabs/gaudi: use COMMS to reset device / halt CPU

This is needed because legacy FW 'communication' protocol will soon
become obsolete.
Because COMMS is a boot protocol, communicating through it is supported
only until Linux is loaded to the device CPU, where in that case we
will fallback to the former implementation.

Signed-off-by: Koby Elbaz <kelbaz@habana.ai>
Reviewed-by: Oded Gabbay <ogabbay@kernel.org>
Signed-off-by: Oded Gabbay <ogabbay@kernel.org>