genlist: Internal refactoring for the code readability.
genlist: Internal refactoring for the code readability.

Added one more internal variable to reduce unnecessary pointer
redirection too much.
Elm_Genlist_Smart_Data *sd is used many times in those functions but it
was always redirected from psd->wsd. I just cut down the step and made
the code more readable and consistent with other lines of code.

psd->wsd --> sd

tasn/elementary,FlorentRevest/Elementary,FlorentRevest/Elementary,rvandegrift/elementary,FlorentRevest/Elementary,rvandegrift/elementary,tasn/elementary,FlorentRevest/Elementary,rvandegrift/elementary,tasn/elementary,tasn/elementary,rvandegrift/elementary,tasn/elementary