HID: wacom - request tool info only when we get general events

Move wacom_intuos_schedule_prox_event inside wacom_intuos_general
so we don't call it when general event data isn't ready.

Signed-off-by: Ping Cheng <pingc@wacom.com>
Reviewed-by: Jason Gerecke <jason.gerecke@wacom.com>
Signed-off-by: Jiri Kosina <jkosina@suse.cz>