x86: Expand Broadcast to 3 bits

x86: Expand Broadcast to 3 bits

Expand Broadcast to 3 bits so that the number of bytes to broadcast
can be computed as 1 << (Broadcast - 1).  Use it to simplify x86
assembler.

gas/

	* config/tc-i386.c (Broadcast_Operation): Add bytes.
	(build_evex_prefix): Use i.broadcast->bytes.
	(match_broadcast_size): New function.
	(check_VecOperands): Use the broadcast field to compute the
	number of bytes to broadcast directly.  Set i.broadcast->bytes.
	Use match_broadcast_size.

opcodes/

	* i386-gen.c (adjust_broadcast_modifier): New function.
	(process_i386_opcode_modifier): Add an argument for operands.
	Adjust the Broadcast value based on operands.
	(output_i386_opcode): Pass operand_types to
	process_i386_opcode_modifier.
	(process_i386_opcodes): Pass NULL as operands to
	process_i386_opcode_modifier.
	* i386-opc.h (BYTE_BROADCAST): New.
	(WORD_BROADCAST): Likewise.
	(DWORD_BROADCAST): Likewise.
	(QWORD_BROADCAST): Likewise.
	(i386_opcode_modifier): Expand broadcast to 3 bits.
	* i386-tbl.h: Regenerated.