drm/amdgpu: Refine function amdgpu_device_ip_late_init

1. only call late_init when hw_init successful,
   so check status.hw instand of status.valid in late_init.
2. set status.late_initialized true if late_init was not implemented.

Reviewed-by: Alex Deucher <alexander.deucher@amd.com>
Signed-off-by: Rex Zhu <Rex.Zhu@amd.com>
Signed-off-by: Alex Deucher <alexander.deucher@amd.com>