Don't populate the const array header on the stack, instead make it
static.  Makes the object code smaller by over 180 bytes:

Before:
   text	   data	    bss	    dec	    hex	filename
   6003	   1536	      0	   7539	   1d73	surface3_spi.o

After:
   text	   data	    bss	    dec	    hex	filename
   5726	   1632	      0	   7358	   1cbe	surface3_spi.o
Signed-off-by: Colin Ian King <colin.king@canonical.com>
Signed-off-by: Dmitry Torokhov <dmitry.torokhov@gmail.com>