media: ivsc: csi: don't count privacy on as error

Prior to the ongoing command privacy is on, it would return -1 to
indicate the current privacy status, and the ongoing command would
be well executed by firmware as well, so this is not error. This
patch changes its behavior to notify privacy on directly by V4L2
privacy control instead of reporting error.

Fixes: 29006e19 ("media: pci: intel: ivsc: Add CSI submodule")
Cc: stable@vger.kernel.org # for 6.6 and later
Reported-by: Hao Yao <hao.yao@intel.com>
Signed-off-by: Wentong Wu <wentong.wu@intel.com>
Tested-by: Jason Chen <jason.z.chen@intel.com>
Signed-off-by: Sakari Ailus <sakari.ailus@linux.intel.com>
Signed-off-by: Hans Verkuil <hverkuil-cisco@xs4all.nl>