A pointer to a probe callback is passed to the core via
platform_driver_register and so the function must not disappear when the
.init sections are discarded.  Otherwise (if also having HOTPLUG=y)
unbinding and binding a device to the driver via sysfs will result in an
oops as does a device being registered late.

An alternative to this patch is using platform_driver_probe instead of
platform_driver_register plus removing the pointer to the probe function
from the struct platform_driver.

Signed-off-by: Uwe Kleine-König <u.kleine-koenig@pengutronix.de>
Cc: Andrew Morton <akpm@linux-foundation.org>
Cc: David Brownell <dbrownell@users.sourceforge.net>
Cc: Dmitri Vorobiev <dmitri.vorobiev@movial.fi>
Cc: Henrik Kretzschmar <henne@nachtwindheim.de>
Cc: James Bottomley <James.Bottomley@HansenPartnership.com>
Cc: Kay Sievers <kay.sievers@vrfy.org>
Cc: peter fuerst <post@pfrst.de>
Cc: Thomas Bogendoerfer <tsbogend@alpha.franken.de>
Acked-by: Ralf Baechle <ralf@linux-mips.org>
Signed-off-by: Greg Kroah-Hartman <gregkh@suse.de>