drm/nouveau/i2c: create proper chipset-specific class implementations

drivers/gpu/drm/nouveau/Makefile

drivers/gpu/drm/nouveau/core/include/subdev/bios/i2c.h

drivers/gpu/drm/nouveau/core/include/subdev/i2c.h

drivers/gpu/drm/nouveau/core/subdev/bios/i2c.c

drivers/gpu/drm/nouveau/core/subdev/device/nv04.c

drivers/gpu/drm/nouveau/core/subdev/device/nv10.c

drivers/gpu/drm/nouveau/core/subdev/device/nv20.c

drivers/gpu/drm/nouveau/core/subdev/device/nv30.c

drivers/gpu/drm/nouveau/core/subdev/device/nv40.c

drivers/gpu/drm/nouveau/core/subdev/device/nv50.c

drivers/gpu/drm/nouveau/core/subdev/device/nvc0.c

drivers/gpu/drm/nouveau/core/subdev/device/nve0.c

drivers/gpu/drm/nouveau/core/subdev/i2c/aux.c

drivers/gpu/drm/nouveau/core/subdev/i2c/base.c

drivers/gpu/drm/nouveau/core/subdev/i2c/bit.c

drivers/gpu/drm/nouveau/core/subdev/i2c/nv04.c

drivers/gpu/drm/nouveau/core/subdev/i2c/nv4e.c

drivers/gpu/drm/nouveau/core/subdev/i2c/nv50.c

drivers/gpu/drm/nouveau/core/subdev/i2c/nv50.h

drivers/gpu/drm/nouveau/core/subdev/i2c/nv94.c