ubsan: z8k: index 10 out of bounds for type 'unsigned int const[10]'

ubsan: z8k: index 10 out of bounds for type 'unsigned int const[10]'

The fix is the additional ARRAY_SIZE test, the rest just tidies
variable types rather than adding a cast to avoid warnings.

opcodes/
	* z8k-dis.c: Include libiberty.h
	(instr_data_s): Make max_fetched unsigned.
	(z8k_lookup_instr): Make nibl_index and tabl_index unsigned.
	Don't exceed byte_info bounds.
	(output_instr): Make num_bytes unsigned.
	(unpack_instr): Likewise for nibl_count and loop.
	* z8kgen.c (gas <opcode_entry_type>): Make noperands, length and
	idx unsigned.
	* z8k-opc.h: Regenerate.
gas/
	* config/tc-z8k.c (md_begin): Make idx unsigned.
	(get_specific): Likewise for this_index.