ARM: 5874/1: serial21285: fix disable_irq-from-interrupt-handler deadlock

The console hangs during bootup when disable_irq is called from the
transmit interrupt handler (it will wait forever for it's "own"
interrupt in synchronize_irq). Fix by using disable_irq_nosync()
instead.
Signed-off-by: Simon Kagstrom <simon.kagstrom@netinsight.net>
Signed-off-by: Russell King <rmk+kernel@arm.linux.org.uk>

drivers/serial/21285.c

@@ -58,7 +58,7 @@ static const char serial21285_name[] = "Footbridge UART";
 static void serial21285_stop_tx(struct uart_port *port)
 {
 	if (tx_enabled(port)) {
-		disable_irq(IRQ_CONTX);
+		disable_irq_nosync(IRQ_CONTX);
 		tx_enabled(port) = 0;
 	}
 }
@@ -74,7 +74,7 @@ static void serial21285_start_tx(struct uart_port *port)
 static void serial21285_stop_rx(struct uart_port *port)
 {
 	if (rx_enabled(port)) {
-		disable_irq(IRQ_CONRX);
+		disable_irq_nosync(IRQ_CONRX);
 		rx_enabled(port) = 0;
 	}
 }