drm/nouveau/pmu/gv100: initial support

Appears to be compatible with GP102.
Signed-off-by: Ben Skeggs <bskeggs@redhat.com>

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

@@ -2412,6 +2412,7 @@ nv140_chipset = {
 	.mc = gp100_mc_new,
 	.mmu = gv100_mmu_new,
 	.pci = gp100_pci_new,
+	.pmu = gp102_pmu_new,
 	.timer = gk20a_timer_new,
 	.top = gk104_top_new,
 };