habanalabs: add dedicated define for hard reset

Gaudi requires longer waiting during reset due to closing of network ports.
Add this explanation to the relevant comment in the code and add a
dedicated define for this reset timeout period, instead of multiplying
another define.

Signed-off-by: Omer Shpigelman <oshpigelman@habana.ai>
Reviewed-by: Oded Gabbay <oded.gabbay@gmail.com>
Signed-off-by: Oded Gabbay <oded.gabbay@gmail.com>