[TREELIST] Optimize treelist_get_dispinfo().
[TREELIST] Optimize treelist_get_dispinfo().

We save few comparison instructions if some MC_NMTLDISPINFO members
are needed. (If they are not we can just do a bogus assignment of those
members as it does not hurt anybody).

mity/mctrl,mity/mctrl,mity/mctrl,mity/mctrl