Remove ucs-set-table-for-input dead code

Remove ucs-set-table-for-input dead code
This function was removed with ucs-tables.el in 2008.

* lisp/international/mule-cmds.el (set-default-coding-systems):
* lisp/files.el (normal-mode):
Remove guarded calls to ucs-set-table-for-input.

* src/buffer.c (Qucs_set_table_for_input): Remove.
(Fget_buffer_create): Don't call Qucs_set_table_for_input.
(init_buffer_once, syms_of_buffer): Remove Qucs_set_table_for_input.

Fixes: debbugs:9821