platform-drivers: move probe to .devinit.text in drivers/video

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: Adrian Bunk <bunk@stusta.de>
Cc: Alberto Mardegan <mardy@users.sourceforge.net>
Cc: Andrew Morton <akpm@linux-foundation.org>
Cc: Andriy Skulysh <askulysh@gmail.com>
Cc: Antonino Daplas <adaplas@gmail.com>
Cc: Anton Vorontsov <avorontsov@ru.mvista.com>
Cc: Ben Dooks <ben-linux@fluff.org>
Cc: Chandramouli Narayanan <mouli@linux.intel.com>
Cc: Christoph Hellwig <hch@lst.de>
Cc: Frans Pop <ele...