leds-lp55xx: add device reset function in lp5521/5523

 Use explicit each driver function rather than raw command.
 These function will be merged into the lp55xx common driver.

Signed-off-by: Milo(Woogyom) Kim <milo.kim@ti.com>
Signed-off-by: Bryan Wu <cooloney@gmail.com>
2 files changed