sim: Remove full system checks from some pseudo insts.

sim: Remove full system checks from some pseudo insts.

These pseudo insts are less useful outside of full system, but they
should all still work. Removing this check makes it possible to, for
instance, test them in syscall emulation mode, and removes another
difference between the two styles of simulation.

Change-Id: Ia7d29bfc6f7c5c236045d151930fc171a6966799
Reviewed-on: https://gem5-review.googlesource.com/c/public/gem5/+/38485
Reviewed-by: Giacomo Travaglini <giacomo.travaglini@arm.com>
Maintainer: Giacomo Travaglini <giacomo.travaglini@arm.com>
Tested-by: kokoro <noreply+kokoro@google.com>