inode: make __iget() a static inline

bcachefs is switching to an rhashtable for vfs inodes instead of the
standard inode.c hashtable, so we need this exported, or - a static
inline makes more sense for a single atomic_inc().
Signed-off-by: Kent Overstreet <kent.overstreet@linux.dev>

fs/inode.c

@@ -438,14 +438,6 @@ static void init_once(void *foo)
 	inode_init_once(inode);
 }
 
-/*
- * inode->i_lock must be held
- */
-void __iget(struct inode *inode)
-{
-	atomic_inc(&inode->i_count);
-}
-
 /*
  * get additional reference to inode; caller must already hold one.
  */

include/linux/fs.h

@@ -3094,7 +3094,14 @@ static inline bool is_zero_ino(ino_t ino)
 	return (u32)ino == 0;
 }
 
-extern void __iget(struct inode * inode);
+/*
+ * inode->i_lock must be held
+ */
+static inline void __iget(struct inode *inode)
+{
+	atomic_inc(&inode->i_count);
+}
+
 extern void iget_failed(struct inode *);
 extern void clear_inode(struct inode *);
 extern void __destroy_inode(struct inode *);