make __d_alloc() static

no users outside of fs/dcache.c
Signed-off-by: Al Viro <viro@zeniv.linux.org.uk>

fs/dcache.c

@@ -1679,7 +1679,7 @@ EXPORT_SYMBOL(d_invalidate);
  * copied and the copy passed in may be reused after this call.
  */
  
-struct dentry *__d_alloc(struct super_block *sb, const struct qstr *name)
+static struct dentry *__d_alloc(struct super_block *sb, const struct qstr *name)
 {
 	struct dentry *dentry;
 	char *dname;

fs/internal.h

@@ -151,7 +151,6 @@ extern int invalidate_inodes(struct super_block *, bool);
 /*
  * dcache.c
  */
-extern struct dentry *__d_alloc(struct super_block *, const struct qstr *);
 extern int d_set_mounted(struct dentry *dentry);
 extern long prune_dcache_sb(struct super_block *sb, struct shrink_control *sc);
 extern struct dentry *d_alloc_cursor(struct dentry *);