drm/nouveau: Fix a couple of sparse warnings.

Signed-off-by: Francisco Jerez <currojerez@riseup.net>
Signed-off-by: Ben Skeggs <bskeggs@redhat.com>
diff --git a/drivers/gpu/drm/nouveau/nouveau_mem.c b/drivers/gpu/drm/nouveau/nouveau_mem.c
index 2853ba0..4b42bf2 100644
--- a/drivers/gpu/drm/nouveau/nouveau_mem.c
+++ b/drivers/gpu/drm/nouveau/nouveau_mem.c
@@ -371,7 +371,7 @@
 	} else {
 		dev_priv->vram_size = nv_rd32(dev, NV04_FIFO_DATA);
 		dev_priv->vram_size |= (dev_priv->vram_size & 0xff) << 32;
-		dev_priv->vram_size &= 0xffffffff00;
+		dev_priv->vram_size &= 0xffffffff00ll;
 		if (dev_priv->chipset == 0xaa || dev_priv->chipset == 0xac) {
 			dev_priv->vram_sys_base = nv_rd32(dev, 0x100e10);
 			dev_priv->vram_sys_base <<= 12;