acl: make vfs_posix_acl_to_xattr() static

After reworking posix acls this helper isn't used anywhere outside the core
posix acl paths. Make it static.
Signed-off-by: Christian Brauner (Microsoft) <brauner@kernel.org>

fs/posix_acl.c

@@ -884,9 +884,10 @@ EXPORT_SYMBOL (posix_acl_to_xattr);
  * Return: On success, the size of the stored uapi posix acls, on error a
  * negative errno.
  */
-ssize_t vfs_posix_acl_to_xattr(struct user_namespace *mnt_userns,
-			       struct inode *inode, const struct posix_acl *acl,
-			       void *buffer, size_t size)
+static ssize_t vfs_posix_acl_to_xattr(struct user_namespace *mnt_userns,
+				      struct inode *inode,
+				      const struct posix_acl *acl, void *buffer,
+				      size_t size)
 
 {
 	struct posix_acl_xattr_header *ext_acl = buffer;

include/linux/posix_acl_xattr.h

@@ -35,9 +35,6 @@ posix_acl_xattr_count(size_t size)
 #ifdef CONFIG_FS_POSIX_ACL
 struct posix_acl *posix_acl_from_xattr(struct user_namespace *user_ns,
 				       const void *value, size_t size);
-ssize_t vfs_posix_acl_to_xattr(struct user_namespace *mnt_userns,
-			       struct inode *inode, const struct posix_acl *acl,
-			       void *buffer, size_t size);
 #else
 static inline struct posix_acl *
 posix_acl_from_xattr(struct user_namespace *user_ns, const void *value,
@@ -45,13 +42,6 @@ posix_acl_from_xattr(struct user_namespace *user_ns, const void *value,
 {
 	return ERR_PTR(-EOPNOTSUPP);
 }
-static inline ssize_t vfs_posix_acl_to_xattr(struct user_namespace *mnt_userns,
-					     struct inode *inode,
-					     const struct posix_acl *acl,
-					     void *buffer, size_t size)
-{
-	return 0;
-}
 #endif
 
 int posix_acl_to_xattr(struct user_namespace *user_ns,