tracing, kvm: change MARKERS to select instead of depends on

Impact: build fix

fix:

 kernel/trace/Kconfig:42:error: found recursive dependency: TRACING ->
 TRACEPOINTS -> MARKERS -> KVM_TRACE -> RELAY -> KMEMTRACE -> TRACING

markers is a facility that should be selected - not depended on
by an interactive Kconfig entry.
Signed-off-by: NIngo Molnar <mingo@elte.hu>

arch/x86/kvm/Kconfig

@@ -55,7 +55,8 @@ config KVM_AMD
 
 config KVM_TRACE
 	bool "KVM trace support"
-	depends on KVM && MARKERS && SYSFS
+	depends on KVM && SYSFS
+	select MARKERS
 	select RELAY
 	select DEBUG_FS
 	default n