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/init/Kconfig b/init/Kconfig
index d599449..031344f 100644
--- a/init/Kconfig
+++ b/init/Kconfig
@@ -771,11 +771,12 @@
 	  Say Y here to enable the extended profiling support mechanisms used
 	  by profilers such as OProfile.
 
+#
+# Place an empty function call at each tracepoint site. Can be
+# dynamically changed for a probe function.
+#
 config TRACEPOINTS
-	bool "Activate tracepoints"
-	help
-	  Place an empty function call at each tracepoint site. Can be
-	  dynamically changed for a probe function.
+	bool
 
 config MARKERS
 	bool "Activate markers"