leds-lp5521: modify the way of setting led device name

Currently the led device name is fetched from the device_type in
I2C_BOARD_INFO which comes from the platform data.  This name is in turn
used to create an entry in sysfs.

If there exists two or more lp5521 on a particular platform, the
device_type in I2C_BOARD_INFO has to be the same, else lp5521 driver probe
wont be called and if used so, results in run time warning "cannot create
sysfs with same name" and hence a failure.

The name that is used to create sysfs entry is to be passed by the struct
led_platform_data.  Hence adding an element of type const char * and
change in lp5521 driver to use this name in creating the led device if
present else use the name obtained by I2C_BOARD_INFO.

Signed-off-by: Arun Murthy <arun.murthy@stericsson.com>
Acked-by: Samu Onkalo <samu.p.onkalo@nokia.com>
Cc: Ilkka Koskinen <ilkka.koskinen@nokia.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>