V4L/DVB (12330): pxa_camera: Fix Oops in pxa_camera_probe

mclk_get_divisor uses pcdev->soc_host.dev, make sure it is initialized.

Signed-off-by: Antonio Ospite <ospite@studenti.unina.it>
Signed-off-by: Guennadi Liakhovetski <g.liakhovetski@gmx.de>
Signed-off-by: Mauro Carvalho Chehab <mchehab@redhat.com>