markers: Disable markers on RT

No real users and the example code triggers an RCU code path which I'm
too lazy to fix simply because markers should go away anyway and Paul
is replacing that code by preemptibel tree rcu soon.
Signed-off-by: Thomas Gleixner <tglx@linutronix.de>

arch/x86/kvm/Kconfig

@@ -65,7 +65,7 @@ config KVM_AMD
 
 config KVM_TRACE
 	bool "KVM trace support"
-	depends on KVM && SYSFS
+	depends on KVM && SYSFS && !PREEMPTRT
 	select MARKERS
 	select RELAY
 	select DEBUG_FS

init/Kconfig

@@ -1075,6 +1075,7 @@ config TRACEPOINTS
 
 config MARKERS
 	bool "Activate markers"
+	depends on !PREEMPT_RT
 	select TRACEPOINTS
 	help
 	  Place an empty function call at each marker site. Can be

kernel/trace/Kconfig

@@ -60,7 +60,6 @@ config EVENT_TRACING
 	bool
 
 config CONTEXT_SWITCH_TRACER
-	select MARKERS
 	bool
 
 # All tracer options should select GENERIC_TRACER. For those options that are