arch-arm: Implement FEAT_HCX

This is just making the HCRX_EL2 register read/writable;
trapping behaviour will be implemented with further extensions

Change-Id: Id1ec42a754b7d999782edde3a8ec6c6099e3331e
Signed-off-by: Giacomo Travaglini <giacomo.travaglini@arm.com>
Reviewed-on: https://gem5-review.googlesource.com/c/public/gem5/+/70939
Maintainer: Jason Lowe-Power <power.jg@gmail.com>
Reviewed-by: Richard Cooper <richard.cooper@arm.com>
Tested-by: kokoro <noreply+kokoro@google.com>
4 files changed