David Brownell <david-b@pacbell.net> Update docs to say that "arm7_9 dbgrq enable" is the default

on ARM9 cores, and update the DaVinci config files so they
no longer explicitly specify it.

git-svn-id: svn://svn.berlios.de/openocd/trunk@2484 b42882b7-edfa-0310-969c-e2dbd0fdcd60