forked from Mirrors/opensbi

- Completed TODO in `system_opcode_insn` to ensure CSR read/write instruction handling. - Refactored to use new macros `GET_RS1_NUM` and `GET_CSR_NUM`. - Updated `GET_RM` macro and replaced hardcoded funct3 values with constants (`CSRRW`, `CSRRS`, `CSRRC`, etc.). - Removed redundant `GET_RM` from `riscv_fp.h`. - Improved validation and error handling for CSR instructions. This patch enhances the clarity and correctness of CSR handling in `system_opcode_insn`. Signed-off-by: Dongdong Zhang <zhangdongdong@eswincomputing.com> Reviewed-by: Anup Patel <anup@brainfault.org>