Simplify JTAG automake input file:

- Consolidate all individual driver variables into DRIVERFILES.
  - Eliminates all empty 'else' conditional clauses.
- Move minidriver files to top of file.
- Use MINIDRIVER conditional to build only driver(s) that will be linked.
- Eliminate superfluous whitespace.


git-svn-id: svn://svn.berlios.de/openocd/trunk@2176 b42882b7-edfa-0310-969c-e2dbd0fdcd60