drm/nouveau/disp/gv100: make gv100_disp_wimm static

Sparse reports this issue
wimmgv100.c:39:1: warning: symbol 'gv100_disp_wimm' was not declared. Should it be static?

This variable is only used in wimmgv100.c.  Single file variables should be static.
So use static as its storage-class specifier.
Signed-off-by: Tom Rix <trix@redhat.com>
Reviewed-by: Lyude Paul <lyude@redhat.com>
Signed-off-by: Lyude Paul <lyude@redhat.com>
Link: https://patchwork.freedesktop.org/patch/msgid/20220425130050.1643103-1-trix@redhat.com

drivers/gpu/drm/nouveau/nvkm/engine/disp/wimmgv100.c

@@ -35,7 +35,7 @@ gv100_disp_wimm_intr(struct nv50_disp_chan *chan, bool en)
 	nvkm_mask(device, 0x611da8, mask, data);
 }
 
-const struct nv50_disp_chan_func
+static const struct nv50_disp_chan_func
 gv100_disp_wimm = {
 	.init = gv100_disp_dmac_init,
 	.fini = gv100_disp_dmac_fini,