wait: using uninitialized member of wait queue

The "flags" member of "struct wait_queue_t" is used in several places in
the kernel code without beeing initialized by init_wait().  "flags" is
used in bitwise operations.

If "flags" not initialized then unexpected behaviour may take place.
Incorrect flags might used later in code.

Added initialization of "wait_queue_t.flags" with zero value into
"init_wait".

Signed-off-by: Evgeny Kuznetsov <EXT-Eugeny.Kuznetsov@nokia.com>
[ The bit we care about does end up being initialized by both
   prepare_to_wait() and add_to_wait_queue(), so this doesn't seem to
   cause actual bugs, but is definitely the right thing to do -Linus ]
Signed-off-by: Linus Torvalds <torvalds@linux-foundation.org>
diff --git a/include/linux/wait.h b/include/linux/wait.h
index 0836ccc..3efc9f3 100644
--- a/include/linux/wait.h
+++ b/include/linux/wait.h
@@ -614,6 +614,7 @@
 		(wait)->private = current;				\
 		(wait)->func = autoremove_wake_function;		\
 		INIT_LIST_HEAD(&(wait)->task_list);			\
+		(wait)->flags = 0;					\
 	} while (0)
 
 /**