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: Paul Gortmaker <paul.gortmaker@windriver.com>
CC: Andrew Morton <akpm@linux-foundation.org>
CC: Felipe Balbi <balbi@ti.com>
Signed-off-by: Greg Kroah-Hartman <gregkh@linuxfoundation.org>