arch-riscv: ignore writes to SXL/UXL fields in status register.

We currently only support SXL=UXL=2 (64 bit). These fields are WARL,
so that we have to make sure that no other value can be set.

Change-Id: I62ddc7d68b8c31ca655ba1ccee7a294912f46b09
Reviewed-on: https://gem5-review.googlesource.com/c/public/gem5/+/25651
Tested-by: kokoro <noreply+kokoro@google.com>
Reviewed-by: Jason Lowe-Power <power.jg@gmail.com>
Maintainer: Jason Lowe-Power <power.jg@gmail.com>
1 file changed