hw/riscv: opentitan: Drop "hartid-base" and "priority-base" initialization

hw/riscv: opentitan: Drop "hartid-base" and "priority-base" initialization

"hartid-base" and "priority-base" are zero by default. There is no
need to initialize them to zero again.

Signed-off-by: Bin Meng <bmeng@tinylab.org>
Reviewed-by: Wilfred Mallawa <wilfred.mallawa@wdc.com>
Reviewed-by: Alistair Francis <alistair.francis@wdc.com>
Message-Id: <20221211030829.802437-15-bmeng@tinylab.org>
Signed-off-by: Alistair Francis <alistair.francis@wdc.com>