target/riscv: Adjust vector address with mask

target/riscv: Adjust vector address with mask

The mask comes from the pointer masking extension, or the max value
corresponding to XLEN bits.

Signed-off-by: LIU Zhiwei <zhiwei_liu@c-sky.com>
Acked-by: Alistair Francis <alistair.francis@wdc.com>
Reviewed-by: Richard Henderson <richard.henderson@linaro.org>
Message-id: 20220120122050.41546-20-zhiwei_liu@c-sky.com
Signed-off-by: Alistair Francis <alistair.francis@wdc.com>