nvk: SPDX everything

I chose to use "Collabora Ldt. and Red Hat Inc." as the author line.  I
could have gone through and manually checked every single file but I
think it's better to spread the blame around.  No one should actually
trust those lines anyway.  That's what git blame is for.

Acked-by: Karol Herbst <kherbst@redhat.com>
Part-of: <https://gitlab.freedesktop.org/mesa/mesa/-/merge_requests/25085>

src/nouveau/vulkan/nvk_buffer.c

@@ -1,3 +1,7 @@
+/*
+ * Copyright © 2022 Collabora Ltd. and Red Hat Inc.
+ * SPDX-License-Identifier: MIT
+ */
 #include "nvk_buffer.h"
 
 #include "nvk_entrypoints.h"