Input: wacom - only register once the MODULE_* macros

Putting the various MODULE_* makes them appear several times in modinfo
because wacom.h is used both in wacom_sys.c and wacom_wac.h.
Having the macros near the module declaration makes them appear only once.

Add also MODULE_VERSION(DRIVER_VERSION) to export the current version
number.

Signed-off-by: Benjamin Tissoires <benjamin.tissoires@redhat.com>
Signed-off-by: Dmitry Torokhov <dmitry.torokhov@gmail.com>