most: usb: replace snprintf in show functions with sysfs_emit

coccicheck complains about the use of snprintf() in sysfs show
functions:
WARNING use scnprintf or sprintf

Use sysfs_emit instead of scnprintf, snprintf or sprintf makes more
sense.

Reported-by: Zeal Robot <zealci@zte.com.cn>
Signed-off-by: Jing Yao <yao.jing2@zte.com.cn>
Link: https://lore.kernel.org/r/20211110025341.136194-1-yao.jing2@zte.com.cn


Signed-off-by: Greg Kroah-Hartman <gregkh@linuxfoundation.org>