drm/nouveau/mmu: fix typo in comment

Spelling mistake (triple letters) in comment.
Detected with the help of Coccinelle.
Signed-off-by: Julia Lawall <Julia.Lawall@inria.fr>
Reviewed-by: Lyude Paul <lyude@redhat.com>
[also fix double space]
Signed-off-by: Lyude Paul <lyude@redhat.com>
Link: https://patchwork.freedesktop.org/patch/msgid/20220521111145.81697-57-Julia.Lawall@inria.fr

drivers/gpu/drm/nouveau/nvkm/subdev/mmu/vmm.c

@@ -280,7 +280,7 @@ nvkm_vmm_unref_ptes(struct nvkm_vmm_iter *it, bool pfn, u32 ptei, u32 ptes)
 	if (desc->type == SPT && (pgt->refs[0] || pgt->refs[1]))
 		nvkm_vmm_unref_sptes(it, pgt, desc, ptei, ptes);
 
-	/* PT no longer neeed?  Destroy it. */
+	/* PT no longer needed? Destroy it. */
 	if (!pgt->refs[type]) {
 		it->lvl++;
 		TRA(it, "%s empty", nvkm_vmm_desc_type(desc));