drm/amdgpu: increase bad page number for umc ras query

One piece of umc normalizing address can be mapped to 16 pieces of
physical address in each umc channel on ALDEBARAN.

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>