md/raid5: Un-nest struct raid5_percpu definition

Sparse reports many warnings of the form:
  drivers/md/raid5.c:1476:16: warning: dereference of noderef expression

This is because all struct raid5_percpu definitions get marked as
__percpu when really only the pointer in r5conf should have that
annotation.

Fix this by moving the defnition of raid5_precpu out of the definition
of struct r5conf.
Signed-off-by: Logan Gunthorpe <logang@deltatee.com>
Reviewed-by: Christoph Hellwig <hch@lst.de>
Signed-off-by: Song Liu <song@kernel.org>

drivers/md/raid5.h

@@ -560,6 +560,16 @@ struct r5pending_data {
 	struct bio_list bios;
 };
 
+struct raid5_percpu {
+	struct page	*spare_page; /* Used when checking P/Q in raid6 */
+	void		*scribble;  /* space for constructing buffer
+				     * lists and performing address
+				     * conversions
+				     */
+	int             scribble_obj_size;
+	local_lock_t    lock;
+};
+
 struct r5conf {
 	struct hlist_head	*stripe_hashtbl;
 	/* only protect corresponding hash list and inactive_list */
@@ -635,15 +645,7 @@ struct r5conf {
 					    */
 	int			recovery_disabled;
 	/* per cpu variables */
-	struct raid5_percpu {
-		struct page	*spare_page; /* Used when checking P/Q in raid6 */
-		void		*scribble;  /* space for constructing buffer
-					     * lists and performing address
-					     * conversions
-					     */
-		int             scribble_obj_size;
-		local_lock_t    lock;
-	} __percpu *percpu;
+	struct raid5_percpu __percpu *percpu;
 	int scribble_disks;
 	int scribble_sectors;
 	struct hlist_node node;