what:
some os preemption path is messed up with world switch preemption
fix:
cleanup those logics so os preemption not mixed with world switch
this patch is a general fix for issues comes from SRIOV MCBP, but
there is still UMD side issues not resovlved yet, so this patch
cannot fix all world switch bug.
Signed-off-by: Monk Liu <Monk.Liu@amd.com> Acked-by: Hawking Zhang <Hawking.Zhang@amd.com> Signed-off-by: Alex Deucher <alexander.deucher@amd.com>