tty/serial: at91: fix bad offset for UART timeout register

With SAMA5D2, the UART has hw timeout but the offset of the register to
define this value is not the same as the one for USART.
When using the new UART, the value of this register was 0 so we never
get timeout irqs. It involves that when using DMA, we were stuck until
the execution of the dma callback which happens when a buffer is full
(so after receiving 2048 bytes).

Signed-off-by: Ludovic Desroches <ludovic.desroches@atmel.com>
Acked-by: Nicolas Ferre <nicolas.ferre@atmel.com>
Signed-off-by: Greg Kroah-Hartman <gregkh@linuxfoundation.org>
diff --git a/include/linux/atmel_serial.h b/include/linux/atmel_serial.h
index ee696d7..5a4d664 100644
--- a/include/linux/atmel_serial.h
+++ b/include/linux/atmel_serial.h
@@ -119,7 +119,8 @@
 #define ATMEL_US_BRGR		0x20	/* Baud Rate Generator Register */
 #define	ATMEL_US_CD		GENMASK(15, 0)	/* Clock Divider */
 
-#define ATMEL_US_RTOR		0x24	/* Receiver Time-out Register */
+#define ATMEL_US_RTOR		0x24	/* Receiver Time-out Register for USART */
+#define ATMEL_UA_RTOR		0x28	/* Receiver Time-out Register for UART */
 #define	ATMEL_US_TO		GENMASK(15, 0)	/* Time-out Value */
 
 #define ATMEL_US_TTGR		0x28	/* Transmitter Timeguard Register */