media: i2c/hi556: add a new mode 1296x722 settings

Add a new mode - 16:9 resolution 1296x722 for hi556.

Signed-off-by: Bingbu Cao <bingbu.cao@intel.com>
Signed-off-by: Qingwu Zhang <qingwu.zhang@intel.com>
Signed-off-by: Sakari Ailus <sakari.ailus@linux.intel.com>
Signed-off-by: Hans Verkuil <hverkuil-cisco@xs4all.nl>