IDR IDs are signed, so struct ib_uobject.id should be signed.  This
avoids some sparse pointer signedness warnings.
Signed-off-by: Roland Dreier <rolandd@cisco.com>
        struct ib_ucontext     *context;        /* associated user context */
        void                   *object;         /* containing object */
        struct list_head        list;           /* link to context's list */
-       u32                     id;             /* index into kernel idr */
+       int                     id;             /* index into kernel idr */
        struct kref             ref;
        struct rw_semaphore     mutex;          /* protects .live */
        int                     live;