net: fec_mpc52xx: add missing kernel-doc for @may_sleep

Add the missing @may_sleep parameter description to the
mpc52xx_fec_stop kernel-doc comment.

Signed-off-by: Rosen Penev <rosenp@gmail.com>
Reviewed-by: Andrew Lunn <andrew@lunn.ch>
Reviewed-by: Sebastian Andrzej Siewior <bigeasy@linutronix.de>
Link: https://patch.msgid.link/20260531000042.369043-1-rosenp@gmail.com
Signed-off-by: Jakub Kicinski <kuba@kernel.org>

drivers/net/ethernet/freescale/fec_mpc52xx.c

@@ -692,6 +692,7 @@ static void mpc52xx_fec_start(struct net_device *dev)
 /**
  * mpc52xx_fec_stop
  * @dev: network device
+ * @may_sleep: whether the caller can sleep (e.g., to wait for tx drain)
  *
  * stop all activity on fec and empty dma buffers
  */