dsp5680xx - separate debug from halt

dsp5680xx - separate debug from halt

i had assumed two possible halt/debug states:
  - halted + debug mode
  - running + not debug mode
turns out this one also exists
  - halted + NOT in debug mode
added code to handle this in an appropiate way.

Change-Id: Ia0ddcd55d1890c90d100a9e6f5e84ed8dda812a3
Signed-off-by: Rodrigo L. Rosa <rodrigorosa.lg@gmail.com>
Reviewed-on: http://openocd.zylin.com/220
Tested-by: jenkins
Reviewed-by: Øyvind Harboe <oyvindharboe@gmail.com>