chat: fixing the chat Makefile to prevent it from removing source files that are required by the chat tests
chat: fixing the chat Makefile to prevent it from removing source
files that are required by the chat tests

Change-Id: I382c97d632926e55a25a02abe6581f284100ae31

viksit/chat,vanadium/chat,vanadium/chat,viksit/chat,vanadium/chat,viksit/chat,viksit/chat,vanadium/chat,viksit/chat,vanadium/chat