x86: drop redundant SYSCALL/SYSRET templates

x86: drop redundant SYSCALL/SYSRET templates

The Cpu64 forms are no different in their attributes except for the CPU
flags; there's no need to key these off of anything other than
CpuSYSCALL even for the 64-bit forms. Dropping these improves the
diagnostic on SYSRETQ used in 32-bit code from "unsupported instruction
`sysret'" to "invalid instruction suffix for `sysret'".