drivers/base/cpu: Simplify s*nprintf() usages

Use the simpler sprintf() instead of snprintf() or scnprintf() in a
single-shot sysfs output callbacks where you are very sure that it
won't go over PAGE_SIZE buffer limit.

Signed-off-by: Takashi Iwai <tiwai@suse.de>
Link: https://lore.kernel.org/r/20200311080207.12046-3-tiwai@suse.de
Signed-off-by: Greg Kroah-Hartman <gregkh@linuxfoundation.org>