Minor cleanup to a couple of functions in ada-lang.c.

Minor cleanup to a couple of functions in ada-lang.c.

gdb/ChangeLog:

        * ada-lang.h (ada_find_any_symbol, ada_find_any_type): Delete.
        * ada-lang.c (ada_find_any_type): Add advance declaration.
        Make static.  Replace ada_find_any_symbol by
        ada_find_any_type_symbol.
        (ada_find_any_type_symbol): Renames ada_find_any_symbol.
        Improve function description.  Make static.
        (ada_find_renaming_symbol, find_old_style_renaming_symbol):
        Replace ada_find_any_symbol by ada_find_any_type_symbol.