Move the discussion of the "scan_chain" command up to go with
the presentation of that topic in the TAP declaration chapter.

This makes the presentation of the TAP and target lists be
parallel, which will be something of an aid to understanding
that they are different (and how).


git-svn-id: svn://svn.berlios.de/openocd/trunk@2223 b42882b7-edfa-0310-969c-e2dbd0fdcd60