drivers/tty/serial/mpc52xx_uart.c: fix typo in C comment

Fix reference on PPC_MPC52xx in C comment after #endif.
Signed-off-by: NValentin Rothberg <valentinrothberg@gmail.com>
Reviewed-by: NPeter Hurley <peter@hurleysoftware.com>
Signed-off-by: NGreg Kroah-Hartman <gregkh@linuxfoundation.org>

drivers/tty/serial/mpc52xx_uart.c

@@ -405,7 +405,7 @@ static struct psc_ops mpc5200b_psc_ops = {
 	.get_mr1 = mpc52xx_psc_get_mr1,
 };
 
-#endif /* CONFIG_MPC52xx */
+#endif /* CONFIG_PPC_MPC52xx */
 
 #ifdef CONFIG_PPC_MPC512x
 #define FIFO_512x(port) ((struct mpc512x_psc_fifo __iomem *)(PSC(port)+1))