habanalabs: keep a record of completed CS outcomes

Often, the user is not interested in the completion timestamp of all
command submissions.
A common situation is, for example, when the user submits a burst of,
possibly, several thousands of commands, then request the completion
timestamp of only couple of specific key commands from all the burst.
The problem is that currently, the outcome of the early commands may be
lost, due to a large amount of later commands, that the user does not
really care about.

This patch creates a separate store with the outcomes of commands the
user has mark explicitly as interested in. This store does not mix the
marked commands with the unmarked ones, hence the data there will
survive for much longer.

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