When channel-context is not enabled, all vifs belong to
the first context, but it is not configured as 'assigned'.

Fix misc debugfs file to print out info for non-assigned
contexts, and also print whether ctx is assigned or not.
Signed-off-by: NBen Greear <greearb@candelatech.com>
Signed-off-by: NJohn W. Linville <linville@tuxdriver.com>