staging: most: configfs: use strlcpy

This patch uses strlcpy to copy data provided by userspace in order
to not overflow the allocated space.

Signed-off-by: Christian Gromm <christian.gromm@microchip.com>
Link: https://lore.kernel.org/r/1576238662-16512-5-git-send-email-christian.gromm@microchip.com


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