target/riscv: Add asserts for out-of-bound access

target/riscv: Add asserts for out-of-bound access

Coverity complained about the possible out-of-bounds access with
counter_virt/counter_virt_prev because these two arrays are
accessed with privilege mode. However, these two arrays are accessed
only when virt is enabled. Thus, the privilege mode can't be M mode.

Add the asserts anyways to detect any wrong usage of these arrays
in the future.

Suggested-by: Peter Maydell <peter.maydell@linaro.org>
Signed-off-by: Atish Patra <atishp@rivosinc.com>
Fixes: Coverity CID 1558459
Fixes: Coverity CID 1558462
Reviewed-by: Alistair Francis <alistair.francis@wdc.com>
Message-ID: <20240724-fixes-v1-1-4a64596b0d64@rivosinc.com>
Signed-off-by: Alistair Francis <alistair.francis@wdc.com>