virtmgr: update comment about input files w.r.t. treble am: 279783a555

Original change: https://android-review.googlesource.com/c/platform/packages/modules/Virtualization/+/3548917

Change-Id: If6cd2ba44bcc5741c826192fee5bd0811df95028
Signed-off-by: Automerger Merge Worker <android-build-automerger-merge-worker@system.gserviceaccount.com>