drm/amdgpu: Fix panic during gpu reset

Clear the flag after hw suspend, otherwise it skips the corresponding hw
resume.

Signed-off-by: xinhui pan <xinhui.pan@amd.com>
Reviewed-by: Hawking Zhang <Hawking.Zhang@amd.com>
Signed-off-by: Alex Deucher <alexander.deucher@amd.com>