target/riscv: Force disable extensions if priv spec version does not match

target/riscv: Force disable extensions if priv spec version does not match

We should disable extensions in riscv_cpu_realize() if minimum required
priv spec version is not satisfied. This also ensures that machines with
priv spec v1.11 (or lower) cannot enable H, V, and various multi-letter
extensions.

Fixes: a775398be2e9 ("target/riscv: Add isa extenstion strings to the device tree")
Reviewed-by: Alistair Francis <alistair.francis@wdc.com>
Signed-off-by: Anup Patel <apatel@ventanamicro.com>
Signed-off-by: Rahul Pathak <rpathak@ventanamicro.com>
Message-Id: <20220630061150.905174-3-apatel@ventanamicro.com>
Signed-off-by: Alistair Francis <alistair.francis@wdc.com>