This patch also adds relevant tests. Regression tested on aarch64-none-elf,
and no regression found.
---
 gas/testsuite/gas/aarch64/sysreg/sysreg.d | 5 +++++
 gas/testsuite/gas/aarch64/sysreg/sysreg.s | 5 +++++
 opcodes/aarch64-sys-regs.def              | 1 +
 3 files changed, 11 insertions(+)