dell_rbu: use scnprintf() instead of less secure sprintf()

Reading 0 bytes from /sys/devices/platform/dell_rbu/image_type or
/sys/devices/platform/dell_rbu/packet_size by an ordinary user causes an
oops.

Signed-off-by: Pavel Roskin <proski@gnu.org>
Signed-off-by: Linus Torvalds <torvalds@linux-foundation.org>
1 file changed