drm/nouveau/mmu/gp100: initial support

GP100 still supports the previous generations' page table layout, which
we will temporarily make use of here.

Proper support for the new MMU layout requires some rework to the common
MMU code, which is in progress.
Signed-off-by: NBen Skeggs <bskeggs@redhat.com>

drivers/gpu/drm/nouveau/nvkm/engine/device/base.c

@@ -2156,6 +2156,7 @@ nv130_chipset = {
 	.fb = gp100_fb_new,
 	.imem = nv50_instmem_new,
 	.mc = gp100_mc_new,
+	.mmu = gf100_mmu_new,
 	.pci = gp100_pci_new,
 	.timer = gk20a_timer_new,
 	.top = gk104_top_new,