drm/nouveau/gem: lookup VMAs for buffers referenced by pushbuf ioctl

We previously only did this for push buffers, but an upcoming patch will
need to attach fences to all VMAs to resolve another issue.

Signed-off-by: Ben Skeggs <bskeggs@redhat.com>

drivers/gpu/drm/nouveau/nouveau_dma.c

@@ -80,18 +80,10 @@ READ_GET(struct nouveau_channel *chan, uint64_t *prev_get, int *timeout)
 }
 
 void
-nv50_dma_push(struct nouveau_channel *chan, struct nouveau_bo *bo,
-	      int delta, int length)
+nv50_dma_push(struct nouveau_channel *chan, u64 offset, int length)
 {
-	struct nouveau_cli *cli = (void *)chan->user.client;
 	struct nouveau_bo *pb = chan->push.buffer;
-	struct nouveau_vma *vma;
 	int ip = (chan->dma.ib_put * 2) + chan->dma.ib_base;
-	u64 offset;
-
-	vma = nouveau_vma_find(bo, &cli->vmm);
-	BUG_ON(!vma);
-	offset = vma->addr + delta;
 
 	BUG_ON(chan->dma.ib_free < 1);