Add an unset_feature() function to compliment the set_feature() function. This
will be used to disable functions after they have been enabled during
initialization.
Backports commit 08828484a5c1ec55a6cbb4b4d377bfcf41199b5c from qemu
When EL3 is running in AArch32 (or ARMv7 with Security Extensions)
IFAR and DFAR have a secure and a non-secure instance.
Backports commit b848ce2b9cbd38da3f2530fd93dba76dba0621c0 from qemu
Prepare ARMCPRegInfo to support specifying two fieldoffsets per
register definition. This will allow us to keep one register
definition for banked registers (different offsets for secure/
non-secure world).
Also added secure state tracking field and flags. This allows for
identification of the register info secure state.
Backports commit c3e302606253a17568dc3ef30238f102468f7ee1 from qemu