msm: camera: sensor: unregister cci subdev if registration fails

If the CPAS registration is failed, subdev need to be unregistered so that
subdev list entry will not become NULL and other subdev can
be added.

Change-Id: I9bf605bef5e125620ce9ba773c040ab7c5995337
Signed-off-by: Shankar Ravi <rshankar@codeaurora.org>