drm/amd/pm: skip to set mp1 unload state in special case

set mp1 unload state will cause the SMC FW can't accept any SMU message,
skip to set mp1 unload state to avoid following case fail:
- runtime pm case.
- gpu reset case.

Fixes: 72aeb6ee ("drm/amd/pm: fix driver reload SMC firmware fail issue for smu13")
Signed-off-by: Yang Wang <KevinYang.Wang@amd.com>
Reviewed-by: Kenneth Feng <kenneth.feng@amd.com>
Signed-off-by: Alex Deucher <alexander.deucher@amd.com>