Merge "Camera: Document limitation on private reprocessing" into udc-dev am: a7bfaf6d

Original change: https://googleplex-android-review.googlesource.com/c/platform/hardware/interfaces/+/21564886



Change-Id: Iba369be51094345a378b169a6e21d9ec0495c703
Signed-off-by: Automerger Merge Worker <android-build-automerger-merge-worker@system.gserviceaccount.com>