if (MACHINE_HAS_TE) translates to if (0) on !CONFIG_64BIT however the
compiler still warns about invalid shifts within non-reachable code.
So add an explicit ifdef to get rid of this warning:
arch/s390/kernel/ptrace.c: In function ‘update_per_regs’:
arch/s390/kernel/ptrace.c:63:4: warning: left shift count >= width of type [enabled by default]
arch/s390/kernel/ptrace.c:65:4: warning: left shift count >= width of type [enabled by default]