Altix serial: fix

Patch was not tested on hardware
---
In function sn_sal_switch_to_asynch(): drivers/serial/sn_console.c:713:

HZ * SN_SAL_UART_FIFO_DEPTH / SN_SAL_UART_FIFO_SPEED_CPS;

After preprocessing (see defines in patch) this becomes HZ * 16 / 9600 / 10 (associativity from left to right), not equivalent to HZ * 16 / 960.
---

index 019da2e..3a2683b 100644
@@ -61,7 +61,7 @@
 #define SN_SAL_BUFFER_SIZE (64 * (1 << 10))
 
 #define SN_SAL_UART_FIFO_DEPTH 16
-#define SN_SAL_UART_FIFO_SPEED_CPS 9600/10
+#define SN_SAL_UART_FIFO_SPEED_CPS (9600/10)
 
 /* sn_transmit_chars() calling args */
 #define TRANSMIT_BUFFERED    0