When guest received FLR notification from host, it would
lock adapter into reset state. There will be no more
job submission and hardware access after that.

Then it should send a response to host that it has prepared
for host reset.
Signed-off-by: Jiange Zhao <Jiange.Zhao@amd.com>
Signed-off-by: Peng Ju Zhou <PengJu.Zhou@amd.com>
Reviewed-by: Emily.Deng <Emily.Deng@amd.com>
Signed-off-by: Alex Deucher <alexander.deucher@amd.com>