Staging: samsung-laptop: Constify samsung-laptop.c

Change sabi_config to const.
Reduces data, increases text ~200 bytes.

$ size drivers/platform/x86/samsung-laptop.o*
   text	   data	    bss	    dec	    hex	filename
   6933	   5084	   1560	  13577	   3509	drivers/platform/x86/samsung-laptop.o.new
   6765	   5252	   1560	  13577	   3509	drivers/platform/x86/samsung-laptop.o.old

Signed-off-by: Joe Perches <joe@perches.com>
Signed-off-by: Greg Kroah-Hartman <gregkh@suse.de>