V4L/DVB (11756): soc_camera: depends on I2C

soc_camera uses i2c_*() functions and has build errors when CONFIG_I2C=n:

ERROR: "i2c_new_device" [drivers/media/video/soc_camera.ko] undefined!
ERROR: "i2c_get_adapter" [drivers/media/video/soc_camera.ko] undefined!
ERROR: "i2c_put_adapter" [drivers/media/video/soc_camera.ko] undefined!
ERROR: "i2c_unregister_device" [drivers/media/video/soc_camera.ko] undefined!

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