habanalabs: Modify the cs_cnt of a CB to be atomic

Modify the CS counter of a CB to be atomic, so no locking is required
when it is being modified or read.

Signed-off-by: Tomer Tayar <ttayar@habana.ai>
Reviewed-by: Oded Gabbay <ogabbay@kernel.org>
Signed-off-by: Oded Gabbay <ogabbay@kernel.org>