aarch64: Add 128-bit system register flags
In preparation for the implementation of 128-bit system register
support across the toolchain, this patch adds the feature flag
F_REG_128 and adds it to relevant system registers in
`aarch64-sys-regs.def'.
Given the shared nature of this file, this change is made necessary
initially to implement argument validation in the `__arm_rsr128' and
`__armwsr128' ACLE intrinsics in GCC, but will be of subsequent use in
the binutils implementation of the corresponding `mrrs' and `msrr'
instructions.
Regression tested on aarch64-linux-gnu, no regressions.
opcodes/ChangeLog:
* aarch64-opc.h (F_REG_128): New flag.
* aarch64-sys-regs.def (par_el1): Add F_REG_128 flag.
(rcwmask_el1): Likewise.
(rcwsmask_el1): Likewise.
(ttbr0_el1): Likewise.
(ttbr0_el12): Likewise.
(ttbr0_el2): Likewise.
(ttbr1_el1): Likewise.
(ttbr1_el12): Likewise.
(ttbr1_el2): Likewise.
(vttbr_el2): Likewise.