This adds a 'ch' command which prints/sets which channels are active
This handles all the async output; the remaining debug commands will
be refactored to use ccprintf() / ccputs() in a followup CL.
Signed-off-by: Randall Spangler <rspangler@chromium.org>
BUG=chrome-os-partner:7464
TEST=manual
ch --> all channels active
ch 0x100 -> just port80 active
powerbtn -> system boots; only port 80 codes shown on console
Change-Id: I9efc43acec919b62b78c2c82c61946d32380adfe