drm/nouveau/falcon: use vmalloc to create firwmare copies

Some firmware images may be large (64K), so using kmalloc memory is
inappropriate for them. Use vmalloc instead, to avoid high-order
allocation failures.

Signed-off-by: Ilia Mirkin <imirkin@alum.mit.edu>
Cc: stable@vger.kernel.org

diff --cc drivers/gpu/drm/nouveau/core/engine/falcon.c
Simple merge