media: ivsc: csi: Don't parse remote endpoints

The driver parsed, besides its own endpoint on the sink, the remote
upstream endpoint that most likely is a sensor, and took the number of
lanes from that. Instead obtain the number of lanes from the local
endpoint.

Signed-off-by: Sakari Ailus <sakari.ailus@linux.intel.com>
Tested-by: Wentong Wu <wentong.wu@intel.com>
Signed-off-by: Hans Verkuil <hverkuil-cisco@xs4all.nl>