habanalabs: handle skip multi-CS if handling not done

This patch fixes issue in which we have timeout for multi-CS although
the CS in the list actually completed.

Example scenario (the two threads marked as WAIT for the thread that
handles the wait_for_multi_cs and CMPL as the thread that signal
completion for both CS and multi-CS):
1. Submit CS with sequence X
2. [WAIT]: call wait_for_multi_cs with single CS X
3. [CMPL]: CS X do invoke complete_all for both CS and multi-CS
           (multi_cs_completion_done still false)
4. [WAIT]: enter poll_fences, reinit the completion and find the CS
           as completed when asking on the fence but multi_cs_done is
	   still false it returns that no CS actually completed
5. [CMPL]: set multi_cs_handling_done as true
6. [WAIT]: wait for completion but no CS to awake the wait context
           and hence wait till timeout

Solution: if CS detected as completed in poll_fences but multi_cs_done
          is still false invoke complete_all to the multi-CS completion
	  and so it will not go to sleep in wait_for_completion but
	  rather will have a "second chance" to wait for
	  multi_cs_completion_done.

Signed-off-by: Ohad Sharabi <osharabi@habana.ai>
Reviewed-by: Oded Gabbay <ogabbay@kernel.org>
Signed-off-by: Oded Gabbay <ogabbay@kernel.org>