-current broken due to kernfs changes

[Juan RP <juan%xtrarom.org@localhost>]

Hi, I've upgraded my NetBSD/Xen system to a newer -current kernel
and Xen 2.0.6, booted fine... when trying to create a domU it failed:

Error: Error creating domain: Failed to map domain control interface

Backing out this change seems to work fine again:

Module Name:    src
Committed By:   chs
Date:           Fri May 20 13:16:54 UTC 2005

Modified Files:
        src/sys/miscfs/kernfs: kernfs.h kernfs_vnops.c

Log Message:
kernfs does not support mmap(), remove code that pretends that it does.

Please fix kernfs again, thanks.