Fix the following coccicheck warning:

./drivers/input/tablet/aiptek.c:1629:8-16: WARNING: use scnprintf or
sprintf.

Reported-by: Abaci Robot<abaci@linux.alibaba.com>
Signed-off-by: Jiapeng Chong <jiapeng.chong@linux.alibaba.com>
Link: https://lore.kernel.org/r/1612419191-1078-1-git-send-email-jiapeng.chong@linux.alibaba.comSigned-off-by: Dmitry Torokhov <dmitry.torokhov@gmail.com>