drm/radeon: cleanup VM id handling a bit

Store a reference to the VM into the IB structure, that
makes calculating the IBs address a bit less complicated.

Signed-off-by: Christian König <deathsimple@vodafone.de>
Reviewed-by: Jerome Glisse <jglisse@redhat.com>
diff --git a/drivers/gpu/drm/radeon/r600.c b/drivers/gpu/drm/radeon/r600.c
index 459c251..fd4289b 100644
--- a/drivers/gpu/drm/radeon/r600.c
+++ b/drivers/gpu/drm/radeon/r600.c
@@ -2635,7 +2635,7 @@
 		return r;
 	}
 	WREG32(scratch, 0xCAFEDEAD);
-	r = radeon_ib_get(rdev, ring->idx, &ib, 256);
+	r = radeon_ib_get(rdev, ring->idx, &ib, NULL, 256);
 	if (r) {
 		DRM_ERROR("radeon: failed to get ib (%d).\n", r);
 		return r;