arch-arm: Consolidate Arm FEAT check into single hasExtension

There's no need to have a per extension helper function now
that we rely on ArmExtension objects

We are therefore removing:

* HavePACExt
* HaveLVA
* HaveSecureEL2Ext
* HaveVirtHostExt

Change-Id: I2094c1eb6310506787e5628aa62d0b14e917ab5e
Signed-off-by: Giacomo Travaglini <giacomo.travaglini@arm.com>
Reviewed-on: https://gem5-review.googlesource.com/c/public/gem5/+/59471
Reviewed-by: Andreas Sandberg <andreas.sandberg@arm.com>
Maintainer: Andreas Sandberg <andreas.sandberg@arm.com>
Tested-by: kokoro <noreply+kokoro@google.com>
9 files changed