[fdt] Add function to get the first range in /memory node of fdt am: 2422bdc31e

Original change: https://android-review.googlesource.com/c/platform/packages/modules/Virtualization/+/2619458

Change-Id: I8a24779442953420b2239b50b14b6a50a1669a42
Signed-off-by: Automerger Merge Worker <android-build-automerger-merge-worker@system.gserviceaccount.com>