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 <[e-mail]>
Link: https://patch.msgid.link/[e-mail]
Signed-off-by: Greg Kroah-Hartman <[e-mail]>

drivers/android/binder.c

···
  *
  * 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)