Revert "drm/radeon: hold reference to fences in radeon_sa_bo_new"

This reverts commit 40df18b4, commit
f6ff4f67 upstream.

It causes oopses:
BUG: unable to handle kernel NULL pointer dereference at 0000000000000008
IP: [<ffffffffa010345d>] radeon_fence_ref+0xd/0x50 [radeon]
Signed-off-by: Jiri Slaby <jslaby@suse.cz>
Cc: Nicolai Hähnle <nicolai.haehnle@amd.com>
Cc: Christian König <christian.koenig@amd.com>

drivers/gpu/drm/radeon/radeon_sa.c

@@ -349,13 +349,8 @@ int radeon_sa_bo_new(struct radeon_device *rdev,
 			/* see if we can skip over some allocations */
 		} while (radeon_sa_bo_next_hole(sa_manager, fences, tries));
 
-		for (i = 0; i < RADEON_NUM_RINGS; ++i)
-			radeon_fence_ref(fences[i]);
-
 		spin_unlock(&sa_manager->wq.lock);
 		r = radeon_fence_wait_any(rdev, fences, false);
-		for (i = 0; i < RADEON_NUM_RINGS; ++i)
-			radeon_fence_unref(&fences[i]);
 		spin_lock(&sa_manager->wq.lock);
 		/* if we have nothing to wait for block */
 		if (r == -ENOENT && block) {