lib/: make RUNTIME_TESTS a menuconfig to ease disabling it all

No need to get into the submenu to disable all related config entries.

This makes it easier to disable all RUNTIME_TESTS config options without
entering the submenu.  It will also enable one to see that en/dis-abled
state from the outside menu.

This is only intended to change menuconfig UI, not change the config
dependencies.

Link: http://lkml.kernel.org/r/[email protected]
Signed-off-by: Vincent Legoll <[email protected]>
Cc: Ingo Molnar <[email protected]>
Cc: Byungchul Park <[email protected]>
Cc: Peter Zijlstra <[email protected]>
Cc: "Paul E. McKenney" <[email protected]>
Cc: Josh Poimboeuf <[email protected]>
Cc: Geert Uytterhoeven <[email protected]>
Cc: Randy Dunlap <[email protected]>
Cc: "Luis R. Rodriguez" <[email protected]>
Cc: Nicholas Piggin <[email protected]>
Cc: Thomas Gleixner <[email protected]>
Signed-off-by: Andrew Morton <[email protected]>
Signed-off-by: Linus Torvalds <[email protected]>

lib/Kconfig.debug

@@ -1641,7 +1641,10 @@ config DMA_API_DEBUG
 
 	  If unsure, say N.
 
-menu "Runtime Testing"
+menuconfig RUNTIME_TESTING_MENU
+	bool "Runtime Testing"
+
+if RUNTIME_TESTING_MENU
 
 config LKDTM
 	tristate "Linux Kernel Dump Test Tool Module"
@@ -1929,7 +1932,7 @@ config TEST_DEBUG_VIRTUAL
 
 	  If unsure, say N.
 
-endmenu # runtime tests
+endif # RUNTIME_TESTING_MENU
 
 config MEMTEST
 	bool "Memtest"