HID: wacom: Delete an unnecessary check before kobject_put()
The kobject_put() function tests whether its argument is NULL and then
returns immediately. Thus the test around the call is not needed.
This issue was detected by using the Coccinelle software.
Signed-off-by: Markus Elfring <elfring@users.sourceforge.net>
Signed-off-by: Jiri Kosina <jkosina@suse.cz>