staging: nvec: replace led_classdev_register

Replace the led_classdev_register() with the platform managed version
devm_led_classdev_register() & henceforth remove the redundant
nvec_paz00_remove() function.

Signed-off-by: Hari Prasath Gujulan Elango <hgujulan@visteon.com>
Acked-by: Marc Dietrich <marvin24@gmx.de>
Signed-off-by: Greg Kroah-Hartman <gregkh@linuxfoundation.org>