habanalabs: adjacent timestamps should be more accurate

timestamp events that expire on the same interrupt will get the same
timestamp value

Signed-off-by: Tamir Gilad-Raz <tgiladraz@habana.ai>
Reviewed-by: Oded Gabbay <ogabbay@kernel.org>
Signed-off-by: Oded Gabbay <ogabbay@kernel.org>