LINEMAP_POSITION_FOR_COLUMN had the exact same effect as
linemap_position_for_column, removed it and updated users
to use linemap_position_for_column instead

        libcpp/ChangeLog
	* include/line-map.h (LINEMAP_POSITION_FOR_COLUMN): Remove.
	Update all users to use linemap_position_for_column instead.

        gcc/go/ChangeLog
	* gofrontend/lex.cc (Lex::location): Update to use
	linemap_position_for_column instead.
        (Lex::earlier_location): Likewise.

From-SVN: r177768