drm/radeon/kms: clean up r6xx/r7xx blit init (v2)

Move common code to init function.

v2: make sure the bo is pinned after init as well.

Signed-off-by: Alex Deucher <alexdeucher@gmail.com>
Signed-off-by: Dave Airlie <airlied@redhat.com>
3 files changed