media: uvcvideo: Fix .queue_setup() to check the number of planes

According to documentation of struct vb2_ops the .queue_setup() callback
should return an error if the number of planes parameter contains an
invalid value on input. Fix this instead of ignoring the value.

Signed-off-by: Guennadi Liakhovetski <guennadi.liakhovetski@intel.com>
Reviewed-by: Laurent Pinchart <laurent.pinchart@ideasonboard.com>
Signed-off-by: Hans Verkuil <hans.verkuil@cisco.com>
Signed-off-by: Mauro Carvalho Chehab <mchehab@s-opensource.com>