Add a note explaining that /dev/drvctl is required for proper support
of the NetBSD 5.0+ HAL backend.


(jmcneill)

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$NetBSD: MESSAGE.NetBSD,v 1.1 2008/12/24 13:41:07 jmcneill Exp $

For the NetBSD 5.0+ HAL backend to function properly, your kernel needs
to include /dev/drvctl support. If the /dev/drvctl device node does not
exist, run the following command:

  # cd /dev
  # sh MAKEDEV drvctl

For proper kernel support, the following directive must be in your kernel
config:

  pseudo-device drvct

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