add PPID to default output for b2g-info

often in bug reports I see people include both b2g-ps output AND b2g-info output.  Often the reason for this is because PPID is important, especially in a Nuwa world (it's a great way to confirm that processes are forked from the Nuwa template process and not from b2g proper).

I think raising the visibility of the process architecture by including PPID in the default output of b2g-info could be useful, and we have plenty of horizontal space for it before we hit 72 chars.