leds: [trivial]Remove unnecesary return

the ret is got the status returned by the
led_classdev_register, returning ret if the
led_classdev_register fails and returning 0
if the led_classdev_register success, can be done
by doing just "return ret" at the end.

Signed-off-by: Devendra Naga <devendra.aaru@gmail.com>
Signed-off-by: Bryan Wu <bryan.wu@canonical.com>