PR25344, z80 disassembler recursion

PR25344, z80 disassembler recursion

	PR 25344
	* z80-dis.c (suffix): Don't use a local struct buffer copy.
	Peek at next byte to prevent recursion on repeated prefix bytes.
	Ensure uninitialised "mybuf" is not accessed.
	(print_insn_z80): Don't zero n_fetch and n_used here,..
	(print_insn_z80_buf): ..do it here instead.