HID: logitech-dj: make const array template static

Don't populate the array template  on the stack but instead make it
static. Makes the object code smaller by 10 bytes. Also reformat
the declaration.

Before:
   text	   data	    bss	    dec	    hex	filename
  29376	   9360	    128	  38864	   97d0	drivers/hid/hid-logitech-dj.o

After:
   text	   data	    bss	    dec	    hex	filename
  29270	   9456	    128	  38854	   97c6	drivers/hid/hid-logitech-dj.o

(gcc version 8.3.0, amd64)

Signed-off-by: Colin Ian King <colin.king@canonical.com>
Signed-off-by: Jiri Kosina <jkosina@suse.cz>