staging/zmem: Use lockdep_assert_held instead of spin_is_locked

WARN_ON(!spin_is_locked()) will always trigger on UP.
Use lockdep_assert_held instead.
Signed-off-by: Andi Kleen <ak@linux.intel.com>
Signed-off-by: Greg Kroah-Hartman <gregkh@linuxfoundation.org>

drivers/staging/zcache/tmem.h

@@ -47,7 +47,7 @@
 #define ASSERT_INVERTED_SENTINEL(_x, _y) do { } while (0)
 #endif
 
-#define ASSERT_SPINLOCK(_l)	WARN_ON(!spin_is_locked(_l))
+#define ASSERT_SPINLOCK(_l)	lockdep_assert_held(_l)
 
 /*
  * A pool is the highest-level data structure managed by tmem and