Fixes the following W=1 kernel build warning(s):

 drivers/gpu/drm/nouveau/nvkm/engine/fifo/runl.c:34:1: warning: no previous prototype for ‘nvkm_engn_cgrp_get’ [-Wmissing-prototypes]

Cc: Ben Skeggs <bskeggs@redhat.com>
Cc: Karol Herbst <kherbst@redhat.com>
Cc: Lyude Paul <lyude@redhat.com>
Cc: David Airlie <airlied@gmail.com>
Cc: Daniel Vetter <daniel@ffwll.ch>
Cc: dri-devel@lists.freedesktop.org
Cc: nouveau@lists.freedesktop.org
Signed-off-by: Lee Jones <lee@kernel.org>
---
 drivers/gpu/drm/nouveau/nvkm/engine/fifo/runl.c | 2 +-
 1 file changed, 1 insertion(+), 1 deletion(-)

diff --git a/drivers/gpu/drm/nouveau/nvkm/engine/fifo/runl.c b/drivers/gpu/drm/nouveau/nvkm/engine/fifo/runl.c
index b5836cbc29aa3..93d628d7d508b 100644
--- a/drivers/gpu/drm/nouveau/nvkm/engine/fifo/runl.c
+++ b/drivers/gpu/drm/nouveau/nvkm/engine/fifo/runl.c
@@ -30,7 +30,7 @@
 #include <subdev/timer.h>
 #include <subdev/top.h>
 
-struct nvkm_cgrp *
+static struct nvkm_cgrp *
 nvkm_engn_cgrp_get(struct nvkm_engn *engn, unsigned long *pirqflags)
 {
 	struct nvkm_cgrp *cgrp = NULL;
-- 
2.40.0.rc1.284.g88254d51c5-goog