According to the spec, from section "32.3 OEM SEL Record - Type
E0h-FFh", event types from 0x0e to 0xff do not have a timestamp.
So don't set it when adding those types.  This required putting
the timestamp in a temporary buffer, since it's still required
to set the last addition time.

Signed-off-by: Corey Minyard <cminyard@mvista.com>
Reviewed-by: Cédric Le Goater <clg@kaod.org>