MIPS: sead3: Use generic suspend/resume for LEDs.

Setting the LED_CORE_SUSPENDRESUME flag causes the LED driver core to call
led_classdev_suspend/led_classdev_resume during suspend/resume. Since this is
exactly what the driver's custom suspend/resume callbacks do we can replace them
by setting the LED_CORE_SUSPENDRESUME flag.

Signed-off-by: Lars-Peter Clausen <lars@metafoo.de>
Signed-off-by: Steven J. Hill <Steven.Hill@imgtec.com>