Fix compile-cplus-types.c build errors

Fix compile-cplus-types.c build errors

I see these errors when building with clang:

  CXX    compile/compile-cplus-types.o
/home/emaisin/src/binutils-gdb/gdb/compile/compile-cplus-types.c:306:56: error: cannot pass non-trivial object of type 'compile_scope' to variadic function; expected type from format string was 'void *' [-Wnon-pod-varargs]
        fprintf_unfiltered (gdb_stdlog, "leaving scope %p\n", current);
                                                       ~~     ^~~~~~~
/home/emaisin/src/binutils-gdb/gdb/compile/compile-cplus-types.c:1058:13: error: comparison of two values with different enumeration types ('enum_flags<gcc_cp_qualifiers>::enum_type' (aka 'gcc_cp_qualifiers') and 'gcc_cp_ref_qualifiers') [-Werror,-Wenum-compare]
  if (quals != GCC_CP_REF_QUAL_NONE)
      ~~~~~ ^  ~~~~~~~~~~~~~~~~~~~~

Fix the first one by using host_address_to_string.

Fix the second one by comparing to 0 instead.  I think the current
comparison simply uses the wrong enum type.  Comparing to 0 seems like
the right thing to do, because we want to check whether any flags are
specified.

gdb/ChangeLog:

	* compile/compile-cplus-types.c
	(compile_cplus_instance::leave_scope): Take the address of scope
	object.
	(compile_cplus_instance::convert_qualified_base): Compare quals
	to 0.