drm/radeon: add proper locking to the SA v3

Make the suballocator self containing to locking.

v2: split the bugfix into a seperate patch.
v3: remove some unreleated changes.

Sig-off-by: Christian König <deathsimple@vodafone.de>

Signed-off-by: Dave Airlie <airlied@redhat.com>
2 files changed