target/riscv: Introduce mmuidx_priv

target/riscv: Introduce mmuidx_priv

Use the priv level encoded into the mmu_idx, rather than
starting from env->priv.  We have already checked MPRV+MPP
in riscv_cpu_mmu_index -- no need to repeat that.

Signed-off-by: Richard Henderson <richard.henderson@linaro.org>
Reviewed-by: Alistair Francis <alistair.francis@wdc.com>
Reviewed-by: Weiwei Li <liweiwei@iscas.ac.cn>
Tested-by: Daniel Henrique Barboza <dbarboza@ventanamicro.com>
Message-Id: <20230325105429.1142530-14-richard.henderson@linaro.org>
Message-Id: <20230412114333.118895-14-richard.henderson@linaro.org>
Signed-off-by: Alistair Francis <alistair.francis@wdc.com>