taint: add explicit flag to show whether lock dep is still OK.

Fix up all callers as they were before, with make one change: an
unsigned module taints the kernel, but doesn't turn off lockdep.

Signed-off-by: Rusty Russell <rusty@rustcorp.com.au>

mm/slab.c

@@ -812,7 +812,7 @@ static void __slab_error(const char *function, struct kmem_cache *cachep,
 	printk(KERN_ERR "slab error in %s(): cache `%s': %s\n",
 	       function, cachep->name, msg);
 	dump_stack();
-	add_taint(TAINT_BAD_PAGE);
+	add_taint(TAINT_BAD_PAGE, LOCKDEP_NOW_UNRELIABLE);
 }
 #endif