nv40: use NV34TCL_ constants where available

nv40: use NV34TCL_ constants where available

It was decided to just use the NV34TCL_ constants for constants
common between nv30 and nv40, and deprecate the NV40TCL_ versions.

This patch changes the nv40 driver to use NV34TCL_ constants for
common functionality.

This reduces differences between nv30 and nv40 to ease further
unification.