target/riscv: Use 'bool' type for read_only

The read_only variable is currently declared as an 'int', but it
should really be a 'bool'.

Signed-off-by: Bin Meng <bmeng@tinylab.org>
Reviewed-by: Weiwei Li <liweiwei@iscas.ac.cn>
Reviewed-by: LIU Zhiwei <zhiwei_liu@linux.alibaba.com>
Message-ID: <20230228104035.1879882-8-bmeng@tinylab.org>
Signed-off-by: Palmer Dabbelt <palmer@rivosinc.com>

target/riscv/csr.c

@@ -3775,7 +3775,7 @@ static inline RISCVException riscv_csrrw_check(CPURISCVState *env,
                                                RISCVCPU *cpu)
 {
     /* check privileges and return RISCV_EXCP_ILLEGAL_INST if check fails */
-    int read_only = get_field(csrno, 0xC00) == 3;
+    bool read_only = get_field(csrno, 0xC00) == 3;
     int csr_min_priv = csr_ops[csrno].min_priv_ver;
 
     /* ensure the CSR extension is enabled */