show() must not use snprintf() when formatting the value to be
returned to user space.

Fix the coccicheck warnings:
WARNING: use scnprintf or sprintf.

Use sysfs_emit instead of scnprintf or sprintf makes more sense.
Signed-off-by: Qing Wang <wangqing@vivo.com>
Link: https://lore.kernel.org/r/1634280641-4862-1-git-send-email-wangqing@vivo.comReviewed-by: Hans de Goede <hdegoede@redhat.com>
Signed-off-by: Hans de Goede <hdegoede@redhat.com>