target/riscv/kvm: Fix the group bit setting of AIA

target/riscv/kvm: Fix the group bit setting of AIA

Just as the hart bit setting of the AIA should be calculated as
ceil(log2(max_hart_id + 1)) the group bit setting should be
calculated as ceil(log2(max_group_id + 1)). The hart bits are
implemented by passing max_hart_id to find_last_bit() and adding
one to the result. Do the same for the group bit setting.

Signed-off-by: Andrew Jones <ajones@ventanamicro.com>
Reviewed-by: Daniel Henrique Barboza <dbarboza@ventanamicro.com>
Message-ID: <20240821075040.498945-2-ajones@ventanamicro.com>
Signed-off-by: Alistair Francis <alistair.francis@wdc.com>