leds: lp5521: make several arrays static const

Don't populate the arrays on the stack, instead make them static const.
Makes the object code smaller by over 120 bytes:

Before:
   text	   data	    bss	    dec	    hex	filename
   8999	   4176	     64	  13239	   33b7	drivers/leds/leds-lp5521.o

After:
   text	   data	    bss	    dec	    hex	filename
   8554	   4496	     64	  13114	   333a	drivers/leds/leds-lp5521.o

Signed-off-by: Colin Ian King <colin.king@canonical.com>
Signed-off-by: Jacek Anaszewski <jacek.anaszewski@gmail.com>