habanalabs: fix wait offset handling

Add handling for case where the user doesn't set wait offset,
and keeps it as 0. In such a case the driver will decrement one
from this zero value which will cause the code to wait for
wrong number of signals.

The solution is to treat this case as in legacy wait cs,
and wait for the next signal.

Signed-off-by: farah kassabri <fkassabri@habana.ai>
Reviewed-by: Oded Gabbay <ogabbay@kernel.org>
Signed-off-by: Oded Gabbay <ogabbay@kernel.org>