platform/x86: thinkpad_acpi: Fix coccinelle warnings

coccicheck complains about the use of snprintf() in sysfs show
functions:

WARNING  use scnprintf or sprintf

Use sysfs_emit instead of scnprintf or sprintf makes more sense.

Reported-by: Zeal Robot <zealci@zte.com.cn>
Signed-off-by: Ye Guojin <ye.guojin@zte.com.cn>
Link: https://lore.kernel.org/r/20211018091750.858826-1-ye.guojin@zte.com.cn
Reviewed-by: Hans de Goede <hdegoede@redhat.com>
Signed-off-by: Hans de Goede <hdegoede@redhat.com>