drm/amdgpu: parse legacy RAS bad page mixed with new data in various NPS modes

All legacy RAS bad pages are generated in NPS1 mode, but new bad page
can be generated in any NPS mode, so we can't use retired_page stored
on eeprom directly in non-nps1 mode even for legacy data. We need to
take different actions for different data, new data can be identified
from old data by UMC_CHANNEL_IDX_V2 flag.

Signed-off-by: Tao Zhou <tao.zhou1@amd.com>
Reviewed-by: Hawking Zhang <Hawking.Zhang@amd.com>
Signed-off-by: Alex Deucher <alexander.deucher@amd.com>