HID: wiimote: add sub-device module infrastructure

To avoid loading all sub-device drivers for every Wii Remote, even though
the required hardware might not be available, we introduce a module layer.

The module layer specifies which sub-devices are available on each
device-type. After device detection, we only load the modules for the
detected device. If module loading fails, we unload everything and mark
the device as WIIMOTE_DEV_UNKNOWN. As long as a device is marked as
"unknown", no sub-devices will be used and the device is considered
unsupported.

All the different sub-devices, including KEYS, RUMBLE, BATTERY, LEDS,
ACCELEROMETER, IR and more will be ported in follow-up patches to the new
module layer.

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