lib/interval_tree_test.c: allow the module to be compiled-in

Patch series "lib/interval_tree_test: some debugging improvements".

Here are some patches that update the interval_tree_test module allowing
users to pass finer grained options to run the actual test.

This patch (of 4):

It is a tristate after all, and also serves well for quick debugging.

Link: http://lkml.kernel.org/r/20170518174936.20265-2-dave@stgolabs.net
Signed-off-by: Davidlohr Bueso <dbueso@suse.de>
Signed-off-by: Andrew Morton <akpm@linux-foundation.org>
Signed-off-by: Linus Torvalds <torvalds@linux-foundation.org>

lib/Kconfig.debug

@@ -1594,7 +1594,7 @@ config RBTREE_TEST
 
 config INTERVAL_TREE_TEST
 	tristate "Interval tree test"
-	depends on m && DEBUG_KERNEL
+	depends on DEBUG_KERNEL
 	select INTERVAL_TREE
 	help
 	  A benchmark measuring the performance of the interval tree library