[media] soc-camera: fix compilation breakage in 3 drivers

A recent commit broke compilation of 3 camera drivers: for PXA2x0, OMAP1
and MX1 by using a wrong pointer. Fix them.

Signed-off-by: Guennadi Liakhovetski <g.liakhovetski@gmx.de>
Signed-off-by: Mauro Carvalho Chehab <mchehab@redhat.com>