habanalabs: halt debug engines on user process close

This patch fix a potential bug where a user's process has closed
unexpectedly without disabling the debug engines. In that case, the debug
engines might continue running but because the user's MMU mappings are
going away, we will get page fault errors.

This behavior is also opposed to the general rule where nothing runs on
the device after the user process closes.

The patch stops the debug H/W engines upon process termination and thus
makes sure nothing runs on the device after the process goes away.

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