drm/amdgpu: Add helper to initialize badpage info

Add a separate function to read badpage data during initialization.
Reading bad pages will need hardware access and cannot be done during
reset. Hence in cases where device needs a full reset during
init itself, attempting to read will cause a deadlock.

Signed-off-by: Lijo Lazar <lijo.lazar@amd.com>
Reviewed-by: Feifei Xu <Feifei.Xu@amd.com>
Reviewed-by: Alex Deucher <alexander.deucher@amd.com>
Acked-by: Rajneesh Bhardwaj <rajneesh.bhardwaj@amd.com>
Tested-by: Rajneesh Bhardwaj <rajneesh.bhardwaj@amd.com>
Signed-off-by: Alex Deucher <alexander.deucher@amd.com>