[PATCH][next] iommufd/iommufd_private.h: Avoid -Wflex-array-member-not-at-end warning

["Gustavo A. R. Silva" <gustavoars@kernel.org>]

-Wflex-array-member-not-at-end was introduced in GCC-14, and we are
getting ready to enable it, globally.

Move the conflicting declaration to the end of the corresponding
structure. Notice that struct iommufd_vevent is a flexible
structure, this is a structure that contains a flexible-array
member.

Fix the following warning:

drivers/iommu/iommufd/iommufd_private.h:621:31: warning: structure containing a flexible array member is not at the end of another structure [-Wflex-array-member-not-at-end]

Signed-off-by: Gustavo A. R. Silva <gustavoars@kernel.org>
---
 drivers/iommu/iommufd/iommufd_private.h | 4 +++-
 1 file changed, 3 insertions(+), 1 deletion(-)

diff --git a/drivers/iommu/iommufd/iommufd_private.h b/drivers/iommu/iommufd/iommufd_private.h
index 627f9b78483a..85d0843ed07b 100644
--- a/drivers/iommu/iommufd/iommufd_private.h
+++ b/drivers/iommu/iommufd/iommufd_private.h
@@ -614,7 +614,6 @@ struct iommufd_veventq {
 	struct iommufd_eventq common;
 	struct iommufd_viommu *viommu;
 	struct list_head node; /* for iommufd_viommu::veventqs */
-	struct iommufd_vevent lost_events_header;
 
 	enum iommu_veventq_type type;
 	unsigned int depth;
@@ -622,6 +621,9 @@ struct iommufd_veventq {
 	/* Use common.lock for protection */
 	u32 num_events;
 	u32 sequence;
+
+	/* Must be last as it ends in a flexible-array member. */
+	struct iommufd_vevent lost_events_header;
 };
 
 static inline struct iommufd_veventq *
-- 
2.43.0