Revert "Documentation: ABI: /sys/devices/system/cpu/cpu#/node"

This reverts commit cba5dd7f.

Commit cba5dd7f duplicates
/sys/devices/system/cpu/cpu#/node entry.
Commit 657348a0 has already added it.

Signed-off-by: Kusanagi Kouichi <slash@ac.auone-net.jp>
Signed-off-by: Jiri Kosina <jkosina@suse.cz>