ceph: fix potential memory leak in init_caches()

[ Upstream commit 1c789249578895bb14ab62b4327306439b754857 ]

There is lack of cache destroy operation for ceph_file_cachep
when failing from fscache register.

Signed-off-by: Chengguang Xu <cgxu519@icloud.com>
Reviewed-by: Ilya Dryomov <idryomov@gmail.com>
Signed-off-by: Ilya Dryomov <idryomov@gmail.com>
Signed-off-by: Sasha Levin <alexander.levin@microsoft.com>
Signed-off-by: Greg Kroah-Hartman <gregkh@linuxfoundation.org>