tracing: clean up tracepoints kconfig structure

do not expose users to CONFIG_TRACEPOINTS - tracers can select it
just fine.

update ftrace to select CONFIG_TRACEPOINTS.

Signed-off-by: Ingo Molnar <mingo@elte.hu>
diff --git a/kernel/trace/Kconfig b/kernel/trace/Kconfig
index 263e9e6..cae2637 100644
--- a/kernel/trace/Kconfig
+++ b/kernel/trace/Kconfig
@@ -14,6 +14,7 @@
 	bool
 	select DEBUG_FS
 	select STACKTRACE
+	select TRACEPOINTS
 
 config FTRACE
 	bool "Kernel Function Tracer"