HID: wiimote: convert IR to module

IR is the last piece that still is handled natively. This patch converts
it into a sub-device module like all other sub-devices. It mainly moves
code and doesn't change semantics.

We also implicitly sync IR data on ir_to_input3 now so the explicit
input_sync() calls are no longer needed.

Signed-off-by: David Herrmann <dh.herrmann@gmail.com>
Signed-off-by: Jiri Kosina <jkosina@suse.cz>