drm/nouveau/device: cleaner abstraction for device resource functions

drivers/gpu/drm/nouveau/include/nvkm/core/device.h

drivers/gpu/drm/nouveau/nouveau_bo.c

drivers/gpu/drm/nouveau/nouveau_chan.c

drivers/gpu/drm/nouveau/nouveau_display.c

drivers/gpu/drm/nouveau/nouveau_ttm.c

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

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

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

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

drivers/gpu/drm/nouveau/nvkm/engine/disp/channv50.c

drivers/gpu/drm/nouveau/nvkm/engine/fifo/chan.c

drivers/gpu/drm/nouveau/nvkm/engine/gr/nv20.c

drivers/gpu/drm/nouveau/nvkm/engine/gr/nv40.c

drivers/gpu/drm/nouveau/nvkm/subdev/bar/gf100.c

drivers/gpu/drm/nouveau/nvkm/subdev/bar/nv50.c

drivers/gpu/drm/nouveau/nvkm/subdev/devinit/fbmem.h

drivers/gpu/drm/nouveau/nvkm/subdev/instmem/nv40.c

drivers/gpu/drm/nouveau/nvkm/subdev/instmem/nv50.c