A README.txt file is added to help the opensource community to use kfdtest
effectively.
After building, run_kfdtest.sh in the building output folder can be used
to run the test.
Change-Id: I9612d9d5a63bd4cdc3a328efd9961d3cc92a6ba5
Signed-off-by: Yong Zhao <yong.zhao@amd.com>