habanalabs: simplify wait for interrupt with timestamp flow

Remove the flag that determines whether to take a timestamp once the
interrupt arrives.
Instead, always take the timestamp once per interrupt.
This is a must for the user-space to measure its graph operations
to evaluate the graph computation time.

Signed-off-by: Yuri Nudelman <ynudelman@habana.ai>
Reviewed-by: Oded Gabbay <ogabbay@kernel.org>
Signed-off-by: Oded Gabbay <ogabbay@kernel.org>