For RAS error scenario, VF guest driver will check mailbox
and set fed flag to avoid unnecessary HW accesses.
additionally, poll for reset completion message first
to avoid accidentally spamming multiple reset requests to host.

v2: add another mailbox check for handling case where kfd detects
timeout first

v3: set host_flr bit and use wait_for_reset
Signed-off-by: Vignesh Chander <Vignesh.Chander@amd.com>
Reviewed-by: Zhigang Luo <Zhigang.Luo@amd.com>
Signed-off-by: Alex Deucher <alexander.deucher@amd.com>