[9fans] rb kernel issue

[erik quanstrom]

i was running vl from /sys/src/cmd/vl/v.out, and got this

        init: starting /bin/rc
        µ# panic: kmapfault: unmapped 0xe0198040

the clue is that v.out was 0 sized after the reboot.  so it appears
that the panic is not correct.  this should be a user fault.

- erik