HID: wiimote: Rename driver to allow multiple source files

Extension and sound support for the wiimote are quite complex and will be
implemented in separate source files. Hence rename the current driver to "-core"
suffix so multiple files can be linked into this module.

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