kprobes: Use CONFIG_PREEMPTION

CONFIG_PREEMPTION is selected by CONFIG_PREEMPT and by
CONFIG_PREEMPT_RT. Both PREEMPT and PREEMPT_RT require the same
functionality which today depends on CONFIG_PREEMPT.

Switch kprobes conditional over to CONFIG_PREEMPTION.
Signed-off-by: Thomas Gleixner <tglx@linutronix.de>
Acked-by: Peter Zijlstra (Intel) <peterz@infradead.org>
Cc: Linus Torvalds <torvalds@linux-foundation.org>
Cc: Masami Hiramatsu <mhiramat@kernel.org>
Cc: Paolo Bonzini <pbonzini@redhat.com>
Cc: Paul E. McKenney <paulmck@linux.ibm.com>
Cc: Peter Zijlstra <peterz@infradead.org>
Cc: Steven Rostedt <rostedt@goodmis.org>
Link: http://lkml.kernel.org/r/20190726212124.516286187@linutronix.deSigned-off-by: Ingo Molnar <mingo@kernel.org>

kernel/kprobes.c

@@ -1906,7 +1906,7 @@ int register_kretprobe(struct kretprobe *rp)
 
 	/* Pre-allocate memory for max kretprobe instances */
 	if (rp->maxactive <= 0) {
-#ifdef CONFIG_PREEMPT
+#ifdef CONFIG_PREEMPTION
 		rp->maxactive = max_t(unsigned int, 10, 2*num_possible_cpus());
 #else
 		rp->maxactive = num_possible_cpus();