reservation.h: build error with lockdep disabled

[Russell King - ARM Linux]

As of 3c3b177a9369 ("reservation: add suppport for read-only access
using rcu") linux/reservation.h uses lockdep macros:

+#define reservation_object_held(obj) lockdep_is_held(&(obj)->lock.base)

This results in build errors when lockdep is disabled as lockdep_is_held()
is only available when lockdep is enabled.  This has been reported today
to break the etnaviv kernel driver, which we're hoping to submit for 4.5.

As this gets used with rcu_dereference_protected(), eg:

static inline struct reservation_object_list *
reservation_object_get_list(struct reservation_object *obj)
{
        return rcu_dereference_protected(obj->fence,
                                         reservation_object_held(obj));
}

I'm guessing that it's not going to be a simple case of making it always
return true or always return false.

Any ideas how to solve this?

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