drm/radeon: rip out the ib pool

It isn't necessary any more and the suballocator seems to perform
even better.

Signed-off-by: Christian König <deathsimple@vodafone.de>
Signed-off-by: Jerome Glisse <jglisse@redhat.com>
Signed-off-by: Dave Airlie <airlied@redhat.com>
5 files changed