leds: ledtrig-transient: fix duration to be msec instead of jiffies

The transient trigger duration is documented to be in msec units, but is
actually in jiffies units. Other time based triggers are in msec units
as well. Fix the timer setup to convert from msec.

This could break an existing userspace that worked around this problem,
but exposing jiffies to userspace is just wrong and would break anyway
if HZ is changed.

Signed-off-by: Rob Herring <robh@kernel.org>
Cc: Shuah Khan <shuahkhan@gmail.com>
Cc: Richard Purdie <rpurdie@rpsys.net>
Cc: linux-leds@vger.kernel.org
Signed-off-by: Jacek Anaszewski <j.anaszewski@samsung.com>