[media] soc_camera: ret is never used. get rid of it

drivers/media/platform/soc_camera/soc_camera.c:1051:8: warning: variable 'ret' set but not used [-Wunused-but-set-variable]

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