leds: tca6507: remove binding comment

Remove the binding comment at the beginning. The information for
platdata is now obsolete and DT binding is documented in device-tree
bindings.

Signed-off-by: Marek Behún <marek.behun@nic.cz>
Cc: NeilBrown <neilb@suse.de>
Cc: Linus Walleij <linus.walleij@linaro.org>
Cc: H. Nikolaus Schaller <hns@goldelico.com>
Signed-off-by: Pavel Machek <pavel@ucw.cz>