Merge "Enable serial console on dragonboard devices." am: b539f3164c am: 3cb0e3d5d1 am: 974ce17886 am: ee2261ccb5 am: 1d40c72dd9

Original change: https://android-review.googlesource.com/c/device/linaro/dragonboard/+/2103407

Change-Id: I69b2b1c7ed44753c0a89769e7c0258f24bd172a9
Signed-off-by: Automerger Merge Worker <android-build-automerger-merge-worker@system.gserviceaccount.com>