target/riscv: Update VS timer whenever htimedelta changes

target/riscv: Update VS timer whenever htimedelta changes

The htimedelta[h] CSR has impact on the VS timer comparison so we
should call riscv_timer_write_timecmp() whenever htimedelta changes.

Fixes: 3ec0fe18a31f ("target/riscv: Add vstimecmp suppor")
Signed-off-by: Anup Patel <apatel@ventanamicro.com>
Reviewed-by: Alistair Francis <alistair.francis@wdc.com>
Message-Id: <20230120125950.2246378-2-apatel@ventanamicro.com>
Signed-off-by: Alistair Francis <alistair.francis@wdc.com>