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>
diff --git a/drivers/serial/21285.c b/drivers/serial/21285.c
index 1e3d193..8681f13 100644
--- a/drivers/serial/21285.c
+++ b/drivers/serial/21285.c
@@ -58,7 +58,7 @@
 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_stop_rx(struct uart_port *port)
 {
 	if (rx_enabled(port)) {
-		disable_irq(IRQ_CONRX);
+		disable_irq_nosync(IRQ_CONRX);
 		rx_enabled(port) = 0;
 	}
 }