[media] V4L: soc-camera: regression fix: calculate .sizeimage in soc_camera.c

A recent patch has given individual soc-camera host drivers a possibility
to calculate .sizeimage and .bytesperline pixel format fields internally,
however, some drivers relied on the core calculating these values for
them, following a default algorithm. This patch restores the default
calculation for such drivers.

Based on initial patch by Guennadi Liakhovetski, found here:

http://www.spinics.net/lists/linux-media/msg31282.html

Except that this covers try_fmt aswell.

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