include/linux/kfifo.h: fix INIT_KFIFO()

DECLARE_KFIFO creates a union with a struct kfifo and a buffer array with
size [size + sizeof(struct kfifo)].

INIT_KFIFO then sets the buffer pointer in struct kfifo to point to the
beginning of the buffer array which means that the first call to kfifo_in
will overwrite members of the struct kfifo.

Signed-off-by: David Härdeman <david@hardeman.nu>
Acked-by: Stefani Seibold <stefani@seibold.net>
Cc: <stable@kernel.org>
Signed-off-by: Andrew Morton <akpm@linux-foundation.org>
Signed-off-by: Linus Torvalds <torvalds@linux-foundation.org>

include/linux/kfifo.h

@@ -86,7 +86,8 @@ union { \
  */
 #define INIT_KFIFO(name) \
 	name = __kfifo_initializer(sizeof(name##kfifo_buffer) - \
-				sizeof(struct kfifo), name##kfifo_buffer)
+				sizeof(struct kfifo), \
+				name##kfifo_buffer + sizeof(struct kfifo))
 
 /**
  * DEFINE_KFIFO - macro to define and initialize a kfifo