libctf: explicitly cast more size_t types used in printf()s

libctf: explicitly cast more size_t types used in printf()s

Unsigned long will always be adequate (the only cases involving an
ssize_t are cases in which no error can be generated, or in which
negative output would require a seriously corrupted file: the latter has
been rewritten on a branch in any case).

Tested on x86_64-pc-linux-gnu, x86_64-unknown-freebsd12.0,
sparc-sun-solaris2.11, i686-pc-cygwin, i686-w64-mingw32.

libctf/
	* ctf-dump.c (ctf_dump_format_type): Cast size_t's used in printf()s.
	(ctf_dump_objts): Likewise.
	(ctf_dump_funcs): Likewise.
	(ctf_dump_member): Likewise.
	(ctf_dump_str): Likewise.