Merge "DRM HAL README.md" am: d4a24d77bb

Original change: https://android-review.googlesource.com/c/platform/hardware/interfaces/+/2395093

Change-Id: I8ce3b98dc0a7d83416e001bd4433f0d5c05d2a4b
Signed-off-by: Automerger Merge Worker <android-build-automerger-merge-worker@system.gserviceaccount.com>