HID: wiimote: Allow direct eeprom access

The wiimote provides direct access to parts of its eeprom. This implements read
support for small chunks of the eeprom. This isn't very fast but prevents the
reader from blocking the wiimote stream for too long.

Write support is not yet supported as the wiimote breaks if we overwrite its
memory. Use hidraw to reverse-engineer the eeprom before implementing write
support here.

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