leds: ktd2692: Drop calling dev_of_node() in ktd2692_parse_dt

output of dev_of_node() is already assigned to "np" variable in
ktd2692_parse_dt(). Use "np" variable to check if OF node is NULL
instead of calling dev_of_node() again.

Signed-off-by: Lad Prabhakar <prabhakar.mahadev-lad.rj@bp.renesas.com>
Signed-off-by: Pavel Machek <pavel@ucw.cz>