db845c: Set baud rate for serial console am: c2840b75d1 am: b213d30154

Original change: https://android-review.googlesource.com/c/device/linaro/dragonboard/+/2261884

Change-Id: I6b0955ffea91614455333e7389f833d8141a9f4b
Signed-off-by: Automerger Merge Worker <android-build-automerger-merge-worker@system.gserviceaccount.com>