target/riscv: Add DisasContext to gen_get_gpr, gen_set_gpr

target/riscv: Add DisasContext to gen_get_gpr, gen_set_gpr

We will require the context to handle RV64 word operations.

Reviewed-by: Alistair Francis <alistair.francis@wdc.com>
Reviewed-by: Bin Meng <bmeng.cn@gmail.com>
Reviewed-by: Philippe Mathieu-Daudé <f4bug@amsat.org>
Signed-off-by: Richard Henderson <richard.henderson@linaro.org>
Message-id: 20210823195529.560295-5-richard.henderson@linaro.org
Signed-off-by: Alistair Francis <alistair.francis@wdc.com>