[binutils-gdb] Fix disassembly of RISC-V CSR instructions under -Mno-aliases

[sergiodj+buildbot at sergiodj dot net]

*** TEST RESULTS FOR COMMIT 04386d9ed5f068b74757bfac01670576e4e59b8a ***

Author: Andrew Waterman <andrew@sifive.com>
Branch: master
Commit: 04386d9ed5f068b74757bfac01670576e4e59b8a

Fix disassembly of RISC-V CSR instructions under -Mno-aliases

This fixes https://github.com/riscv/riscv-binutils-gdb/issues/36.

	* riscv-opc.c (riscv_opcodes): Mark the rd* and csr* aliases as
	INSN_ALIAS.