Documentation: leds/ledtrig-transient: eliminate duplicated word

Drop the doubled word "for".

Signed-off-by: Randy Dunlap <rdunlap@infradead.org>
Acked-by: Jacek Anaszewski <jacek.anaszewski@gmail.com>
Acked-by: Pavel Machek <pavel@ucw.cz>
Cc: Jonathan Corbet <corbet@lwn.net>
Cc: linux-doc@vger.kernel.org
Cc: Jacek Anaszewski <jacek.anaszewski@gmail.com>
Cc: Pavel Machek <pavel@ucw.cz>
Cc: Dan Murphy <dmurphy@ti.com>
Cc: linux-leds@vger.kernel.org
Link: https://lore.kernel.org/r/20200707180414.10467-12-rdunlap@infradead.org


Signed-off-by: Jonathan Corbet <corbet@lwn.net>