V4L/DVB: IR: ir-raw-event: null pointer dereference

The original code dereferenced ir->raw after freeing it and setting it
to NULL.

Signed-off-by: Dan Carpenter <error27@gmail.com>
Acked-by: Jarod Wilson <jarod@redhat.com>
Signed-off-by: Mauro Carvalho Chehab <mchehab@redhat.com>