target/riscv: Add CSR name in the CSR function table

In preparation to generate the CSR register list for GDB stub
dynamically, let's add the CSR name in the CSR function table.

Signed-off-by: Bin Meng <bin.meng@windriver.com>
Reviewed-by: Alistair Francis <alistair.francis@wdc.com>
Message-id: 1610427124-49887-3-git-send-email-bmeng.cn@gmail.com
Signed-off-by: Alistair Francis <alistair.francis@wdc.com>

target/riscv/cpu.h

@@ -472,6 +472,7 @@ typedef int (*riscv_csr_op_fn)(CPURISCVState *env, int csrno,
     target_ulong *ret_value, target_ulong new_value, target_ulong write_mask);
 
 typedef struct {
+    const char *name;
     riscv_csr_predicate_fn predicate;
     riscv_csr_read_fn read;
     riscv_csr_write_fn write;