USB: usbsevseg: convert sysfs snprintf to sysfs_emit

Fix the following coccincheck warning:
drivers/usb/misc/usbsevseg.c:170:8-16:
WARNING: use scnprintf or sprintf

Signed-off-by: Xuezhi Zhang <zhangxuezhi1@coolpad.com>
Link: https://lore.kernel.org/r/20220727124415.8340-1-zhangxuezhi3@gmail.com


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