coreutils 6.9: fix coreutils.texi

coreutils 6.9: fix coreutils.texi

This is used for fixing coreutils 6.9 (GPLv2+) do_installed failed:

[snip]
| coreutils.texi:2499: @itemx must follow @item
| coreutils.texi:2636: @itemx must follow @item
| coreutils.texi:2644: @itemx must follow @item
| coreutils.texi:2654: @itemx must follow @item
| coreutils.texi:2677: @itemx must follow @item
| coreutils.texi:2689: @itemx must follow @item
| coreutils.texi:2820: @itemx must follow @item
| coreutils.texi:3058: @itemx must follow @item
| coreutils.texi:3253: @itemx must follow @item
[snip]

Use '@item' instead of '@itemx' in several places, as Texinfo 5 refuses
to process an '@itemx' that is not preceded by an '@item'.  Ensure that
node extended names in menus and sectioning are consistent, and that
ordering and presence of nodes in menus and in the actual text are
consistent as well.

[YOCTO #5593]

(From OE-Core rev: 04fab782f42b8f5047390042618f9c841b8c3a96)

Signed-off-by: Robert Yang <liezhi.yang@windriver.com>
Signed-off-by: Richard Purdie <richard.purdie@linuxfoundation.org>