Fix incorrect register name in disassembler for fmv,fabs,fneg instructions

Fix incorrect register name in RISC-V disassembler for fmv,fabs,fneg instructions

Signed-off-by: Mikhail Tyutin <m.tyutin@yadro.com>
Reviewed-by: Alistair Francis <alistair.francis@wdc.com>
Message-Id: <3454991f-7f64-24c3-9a36-f5fa2cc389e1@yadro.com>
Signed-off-by: Alistair Francis <alistair.francis@wdc.com>