android: binder: add missing return value documentation for binder_apply_fd_fixups()

The kernel-doc for binder_apply_fd_fixups() was missing a description of
its return value, which triggers a kernel-doc warning.

Add the missing "Return:" entry to doc that the function returns 0 on
success or a negative errno on failure.

Signed-off-by: Sunday Adelodun <adelodunolaoluwa@yahoo.com>
Link: https://patch.msgid.link/20251121111203.21800-2-adelodunolaoluwa@yahoo.com
Signed-off-by: Greg Kroah-Hartman <gregkh@linuxfoundation.org>

Author: sadelodun

drivers/android/binder.c

@@ -4669,6 +4669,8 @@ static int binder_wait_for_work(struct binder_thread *thread,
  *
  * If we fail to allocate an fd, skip the install and release
  * any fds that have already been allocated.
+ *
+ * Return: 0 on success, a negative errno code on failure.
  */
 static int binder_apply_fd_fixups(struct binder_proc *proc,
 				  struct binder_transaction *t)