The MCBP unit test is used to test the functionality of MCBP.
It emualtes to send preemption request and resubmit the unfinished
jobs.

v2: squash in fixes (Alex)
v3: squash in memory leak fix (Jack)
Acked-by: Hawking Zhang <Hawking.Zhang@amd.com>
Signed-off-by: Jack Xiao <Jack.Xiao@amd.com>
Signed-off-by: Alex Deucher <alexander.deucher@amd.com>