drm/nouveau: allocate GPFIFOs and fences coherently

Specify TTM_PL_FLAG_UNCACHED when allocating GPFIFOs and fences to
allow them to be safely accessed by the kernel without being synced
on non-coherent architectures.

Signed-off-by: Alexandre Courbot <acourbot@nvidia.com>
Signed-off-by: Ben Skeggs <bskeggs@redhat.com>
diff --git a/drivers/gpu/drm/nouveau/nouveau_chan.c b/drivers/gpu/drm/nouveau/nouveau_chan.c
index 77c81d6..0f3da86 100644
--- a/drivers/gpu/drm/nouveau/nouveau_chan.c
+++ b/drivers/gpu/drm/nouveau/nouveau_chan.c
@@ -102,7 +102,7 @@
 	chan->drm = drm;
 
 	/* allocate memory for dma push buffer */
-	target = TTM_PL_FLAG_TT;
+	target = TTM_PL_FLAG_TT | TTM_PL_FLAG_UNCACHED;
 	if (nouveau_vram_pushbuf)
 		target = TTM_PL_FLAG_VRAM;