serial: add OMAP-specific defines

OMAP has some extra Interrupt types which can
be really useful for SW. Let's define them
so we can later use those in OMAP's serial driver.
Tested-by: NShubhrajyoti D <shubhrajyoti@ti.com>
Acked-by: NSantosh Shilimkar <santosh.shilimkar@ti.com>
Signed-off-by: NFelipe Balbi <balbi@ti.com>
Signed-off-by: NGreg Kroah-Hartman <gregkh@linuxfoundation.org>

include/linux/serial_reg.h

@@ -40,6 +40,10 @@
 
 #define UART_IIR_BUSY		0x07 /* DesignWare APB Busy Detect */
 
+#define UART_IIR_RX_TIMEOUT	0x0c /* OMAP RX Timeout interrupt */
+#define UART_IIR_XOFF		0x10 /* OMAP XOFF/Special Character */
+#define UART_IIR_CTS_RTS_DSR	0x20 /* OMAP CTS/RTS/DSR Change */
+
 #define UART_FCR	2	/* Out: FIFO Control Register */
 #define UART_FCR_ENABLE_FIFO	0x01 /* Enable the FIFO */
 #define UART_FCR_CLEAR_RCVR	0x02 /* Clear the RCVR FIFO */