drm/amdgpu: update algorithm of umc address conversion

On ALDEBARAN, we need to traverse all column bits higher than
BIT11(C4C3C2) in a row, the shift of R14 bit should be also taken
into account. Retire all pages we find.

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>