aarch64: Add missing system registers [PR27145]

aarch64: Add missing system registers [PR27145]

This patch adds support for various system registers, up to Armv8.7-A.
This includes all the registers that were mentioned in the PR and that
hadn't become supported since.

opcodes/
	PR aarch64/27145
	* aarch64-opc.c (SR_V8_4): Remove duplicate definition.
	(SR_V8_6, SR_V8_7, SR_GIC, SR_AMU): New macros.
	(aarch64_sys_regs): Add missing entries (up to Armv8.7-A).

gas/
	PR aarch64/27145
	* testsuite/gas/aarch64/sysreg-8.s,
	* testsuite/gas/aarch64/sysreg-8.d,
	* testsuite/gas/aarch64/illegal-sysreg-8.s,
	* testsuite/gas/aarch64/illegal-sysreg-8.d,
	* testsuite/gas/aarch64/illegal-sysreg-8.l,
	* testsuite/gas/aarch64/illegal-sysreg-8b.s,
	* testsuite/gas/aarch64/illegal-sysreg-8b.d,
	* testsuite/gas/aarch64/illegal-sysreg-8b.l: New tests.
	* testsuite/gas/aarch64/sysreg.s: Change system register numbers
	to ones that are still unallocated.
	* testsuite/gas/aarch64/sysreg.d: Update accordingly.