btrfs: move btrfs_extref_hash into inode-item.h

Ideally this would be un-inlined, but that is a cleanup for later.  For
now move this into inode-item.h, which is where the extref code lives.
Reviewed-by: Johannes Thumshirn <johannes.thumshirn@wdc.com>
Reviewed-by: Anand Jain <anand.jain@oracle.com>
Signed-off-by: Josef Bacik <josef@toxicpanda.com>
Reviewed-by: David Sterba <dsterba@suse.com>
Signed-off-by: David Sterba <dsterba@suse.com>

fs/btrfs/ctree.h

@@ -475,15 +475,6 @@ static inline u64 btrfs_name_hash(const char *name, int len)
        return crc32c((u32)~1, name, len);
 }
 
-/*
- * Figure the key offset of an extended inode ref
- */
-static inline u64 btrfs_extref_hash(u64 parent_objectid, const char *name,
-                                   int len)
-{
-       return (u64) crc32c(parent_objectid, name, len);
-}
-
 static inline gfp_t btrfs_alloc_write_mask(struct address_space *mapping)
 {
 	return mapping_gfp_constraint(mapping, ~__GFP_FS);

fs/btrfs/inode-item.h

@@ -4,6 +4,7 @@
 #define BTRFS_INODE_ITEM_H
 
 #include <linux/types.h>
+#include <linux/crc32c.h>
 
 struct btrfs_trans_handle;
 struct btrfs_root;
@@ -76,6 +77,12 @@ static inline void btrfs_inode_split_flags(u64 inode_item_flags,
 	*ro_flags = (u32)(inode_item_flags >> 32);
 }
 
+/* Figure the key offset of an extended inode ref. */
+static inline u64 btrfs_extref_hash(u64 parent_objectid, const char *name, int len)
+{
+       return (u64)crc32c(parent_objectid, name, len);
+}
+
 int btrfs_truncate_inode_items(struct btrfs_trans_handle *trans,
 			       struct btrfs_root *root,
 			       struct btrfs_truncate_control *control);