This structure needs to always stick around, even if CONFIG_HOTPLUG
is disabled, otherwise we can oops when trying to probe a device that
was added after the structure is thrown away.

Thanks to Fengguang Wu and Bjørn Mork for tracking this issue down.
Reported-by: Fengguang Wu <fengguang.wu@intel.com>
Reported-by: Bjørn Mork <bjorn@mork.no>
Cc: stable <stable@vger.kernel.org>
CC: Herton Ronaldo Krzesinski <herton@canonical.com>
CC: Hin-Tak Leung <htl10@users.sourceforge.net>
CC: Larry Finger <Larry.Finger@lwfinger.net>
CC: "John W. Linville" <linville@tuxdriver.com>
Signed-off-by: Greg Kroah-Hartman <gregkh@linuxfoundation.org>