kmemleak: Select DEBUG_FS unconditionally in DEBUG_KMEMLEAK

In the past DEBUG_FS used to depend on SYSFS and DEBUG_KMEMLEAK selected
it conditionally. This is no longer the case, so always select DEBUG_FS
via DEBUG_KMEMLEAK.
Signed-off-by: NCatalin Marinas <catalin.marinas@arm.com>

lib/Kconfig.debug

@@ -400,7 +400,7 @@ config DEBUG_KMEMLEAK
 	depends on DEBUG_KERNEL && EXPERIMENTAL && !MEMORY_HOTPLUG && \
 		(X86 || ARM || PPC || S390 || SPARC64 || SUPERH || MICROBLAZE || TILE)
 
-	select DEBUG_FS if SYSFS
+	select DEBUG_FS
 	select STACKTRACE if STACKTRACE_SUPPORT
 	select KALLSYMS
 	select CRC32