serial: 8250: 8250_core: Use dev_name() during request_irq()

Passing "serial" as name during request_irq() results in all serial port
irqs have same name. This does not help much to easily identify which
irq belongs to which serial port instance. Therefore pass dev_name()
during request_irq() so that better identifiable name is listed for
serial ports in cat /proc/interrupts output.

Output of cat /proc/interrupts
Before this patch:
 26:        689          0     GICv2 309 Edge      serial
After this patch:
 26:        696          0     GICv2 309 Edge      2530c00.serial
Signed-off-by: Vignesh R <vigneshr@ti.com>
Signed-off-by: Greg Kroah-Hartman <gregkh@linuxfoundation.org>

drivers/tty/serial/8250/8250_core.c

@@ -218,7 +218,7 @@ static int serial_link_irq_chain(struct uart_8250_port *up)
 		spin_unlock_irq(&i->lock);
 		irq_flags |= up->port.irqflags;
 		ret = request_irq(up->port.irq, serial8250_interrupt,
-				  irq_flags, "serial", i);
+				  irq_flags, dev_name(up->port.dev), i);
 		if (ret < 0)
 			serial_do_unlink(i, up);
 	}