i2o: convert bus code to use dev_groups

The dev_attrs field of struct bus_type is going away soon, dev_groups
should be used instead.  This converts the i2o bus code to use the
correct field.

Cc: Andrew Morton <akpm@linux-foundation.org>
Signed-off-by: Greg Kroah-Hartman <gregkh@linuxfoundation.org>

diff --cc drivers/message/i2o/core.h
Simple merge

diff --cc drivers/message/i2o/device.c
Simple merge

diff --cc drivers/message/i2o/driver.c
Simple merge