Sparse complains that:
drivers/hid/hid-lg4ff.c:288:44: warning: Using plain integer as NULL pointer
drivers/hid/hid-lg4ff.c:311:44: warning: Using plain integer as NULL pointer
Signed-off-by: Dan Carpenter <error27@gmail.com>
Signed-off-by: Jiri Kosina <jkosina@suse.cz>