This adds the hotplug routine for generating hotplug events when devices
are seen on the macio bus.  It uses the attributed created by the sysfs
nodes to generate the hotplug environment vars for userspace.

Since the characters allowed inside the 'compatible' field are NUL
terminated, they are exported as individual OF_COMPATIBLE_# variables,
with OF_COMPATIBLE_N maintaining a count of how many there are.

In order for hotplug to work with macio devices, patches to
module-init-tools and hotplug must be applied.  Those patches are
available at:

ftp://ftp.suse.com/pub/people/jeffm/linux/macio-hotplug/Signed-off-by: NJeff Mahoney <jeffm@suse.com>
Signed-off-by: NLinus Torvalds <torvalds@osdl.org>