aarch64: Make LOR registers conditional on +lor

aarch64: Make LOR registers conditional on +lor

We have a +lor feature flag for the Limited Ordering Regions
extension, but the associated registers didn't use it.

opcodes/
	* aarch64-opc.c (SR_LOR): New macro.
	(aarch64_sys_regs): Use it for lorc_el1, lorea_el1, lorn_el1 and
	lorsa_el1.

gas/
	* testsuite/gas/aarch64/sysreg-7.s: Enable +lor.
	* testsuite/gas/aarch64/illegal-sysreg-7.s: Test for LOR registers
	without +lor.
	* testsuite/gas/aarch64/illegal-sysreg-7.d: Update accordingly.
	* testsuite/gas/aarch64/illegal-sysreg-7.l: Likewise.