Commit 
b8e7a54cd06b0b0174029ef3a7f5a1415a2c28f2 introduced a compile
error if CONFIG_PREEMPT is not set:
arch/s390/kernel/built-in.o: In function `cleanup_io_leave_insn':
/space/kvm/arch/s390/kernel/entry.S:(.text+0xbfce): undefined reference to `preempt_schedule_irq'
This patch hides preempt_schedule_irq if CONFIG_PREEMPT is not set.
Signed-off-by: Christian Borntraeger <borntraeger@de.ibm.com>
Signed-off-by: Martin Schwidefsky <schwidefsky@de.ibm.com>
 .Lexecve_tail: .long   execve_tail
 .Ljump_table:  .long   pgm_check_table
 .Lschedule:    .long   schedule
+#ifdef CONFIG_PREEMPT
 .Lpreempt_schedule_irq:
                .long   preempt_schedule_irq
+#endif
 .Ltrace:       .long   syscall_trace
 .Lschedtail:   .long   schedule_tail
 .Lsysc_table:  .long   sys_call_table