drivers/leds/leds-lp5521.c: add 'name' in the lp5521_led_config

The name of each led channel can be configurable.  For the compatibility,
the name is set to default value(xx:channelN) when 'name' is not defined.

Signed-off-by: Milo(Woogyom) Kim <milo.kim@ti.com>
Acked-by: Linus Walleij <linus.walleij@linaro.org>
Cc: Arun MURTHY <arun.murthy@stericsson.com>
Cc: Srinidhi Kasagar <srinidhi.kasagar@stericsson.com>
Cc: Richard Purdie <rpurdie@rpsys.net>
Signed-off-by: Andrew Morton <akpm@linux-foundation.org>
Signed-off-by: Linus Torvalds <torvalds@linux-foundation.org>