board/common: revert parts of 8353963

Running 'shred' on files stored on eMMC is pointless since the writes
are spread out over other sectors rather than overwriting the content
of the files as it was supposed to on old rotating media.

Signed-off-by: Joachim Wiberg <troglobit@gmail.com>

board/common/rootfs/usr/libexec/infix/mnt

@@ -45,11 +45,6 @@ factory_reset()
     find /sys/class/leds/ -type l -exec sh -c 'echo 100 > $0/brightness' {} \;
     logger $opt -p user.crit -t "$nm" "Resetting to factory defaults."
 
-    # Shred all files to prevent restoring contents
-    find /mnt/cfg -type f -exec shred -zu {} \;
-    find /mnt/var -type f -exec shred -zu {} \;
-
-    # Remove any lingering directories and symlinks as well
     rm -rf /mnt/cfg/* /mnt/var/*
 
     logger $opt -p user.crit -t "$nm" "Factory reset complete."