RISC-V: Set insn info fields correctly when disassembling.

RISC-V: Set insn info fields correctly when disassembling.

	include/
	* opcode/riscv.h (INSN_TYPE, INSN_BRANCH, INSN_CONDBRANCH, INSN_JSR)
	(INSN_DREF, INSN_DATA_SIZE, INSN_DATA_SIZE_SHIFT, INSN_1_BYTE)
	(INSN_2_BYTE, INSN_4_BYTE, INSN_8_BYTE, INSN_16_BYTE): New.

	opcodes/
	* riscv-dis.c (riscv_disassemble_insn): Set insn_type and data_size
	fields.
	* riscv-opc.c (riscv_opcodes): Use new INSN_* flags to annotate insns.