leds-lp55xx: use lp55xx common init function - platform data

LP5521/5523 platform data functions are moved to lp55xx common driver.
 New init function, lp55xx_init_device() is created.

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

drivers/leds/leds-lp55xx-common.h

@@ -58,4 +58,7 @@ extern int lp55xx_read(struct lp55xx_chip *chip, u8 reg, u8 *val);
 extern int lp55xx_update_bits(struct lp55xx_chip *chip, u8 reg,
 			u8 mask, u8 val);
 
+/* common device init functions */
+extern int lp55xx_init_device(struct lp55xx_chip *chip);
+
 #endif /* _LEDS_LP55XX_COMMON_H */