HID: wacom: bits shifted too much for 9th and 10th buttons

commit ce06760ba46b66dae50f2519ae76bd15e89b5710 upstream.

Cintiq 12 has 10 expresskey buttons. The bit shift for the last
two buttons were off by 5.

Fixes: c7f0522a ("HID: wacom: Slim down wacom_intuos_pad processing")

Signed-off-by: Ping Cheng <ping.cheng@wacom.com>
Tested-by: Matthieu Robin <matthieu@macolu.org>
Signed-off-by: Jiri Kosina <jkosina@suse.cz>
Cc: Jason Gerecke <killertofu@gmail.com>
Signed-off-by: Greg Kroah-Hartman <gregkh@linuxfoundation.org>