TTY: irq: Remove IRQF_DISABLED

Since commit [e58aa3d2: genirq: Run irq handlers with interrupts disabled],
We run all interrupt handlers with interrupts disabled
and we even check and yell when an interrupt handler
returns with interrupts enabled (see commit [b738a50a:
genirq: Warn when handler enables interrupts]).

So now this flag is a NOOP and can be removed.

Signed-off-by: Yong Zhang <yong.zhang0@gmail.com>
Acked-by: Tobias Klauser <tklauser@distanz.ch>
Signed-off-by: Greg Kroah-Hartman <gregkh@suse.de>
diff --git a/drivers/tty/serial/68328serial.c b/drivers/tty/serial/68328serial.c
index f549231..a88ef97 100644
--- a/drivers/tty/serial/68328serial.c
+++ b/drivers/tty/serial/68328serial.c
@@ -1306,7 +1306,7 @@
 
 	    if (request_irq(uart_irqs[i],
 			    rs_interrupt,
-			    IRQF_DISABLED,
+			    0,
 			    "M68328_UART", info))
                 panic("Unable to attach 68328 serial interrupt\n");
 	}