cpuidle: sysfs: Use sysfs_emit()/sysfs_emit_at() instead of sprintf()/scnprintf()

The ->show() callbacks in sysfs should use sysfs_emit() or
sysfs_emit_at() when formatting values for user space.

These helpers are the recommended way to ensure correct buffer
handling and consistency across the kernel.

See Documentation/filesystems/sysfs.rst for details.

No functional change intended.

Suggested-by: Joe Perches <joe@perches.com>
Signed-off-by: Vivek Yadav <vivekyadav1207731111@gmail.com>
Link: https://patch.msgid.link/20250919165657.233349-1-vivekyadav1207731111@gmail.com


[ rjw: Minor subject edits ]
Signed-off-by: Rafael J. Wysocki <rafael.j.wysocki@intel.com>