serial: core: Add big-endian iotype

Since most drivers interpret UPIO_MEM32 to mean "little-endian" and use
readl/writel to access the registers, add a parallel UPIO_MEM32BE to
request the use of big-endian MMIO accessors (ioread32be/iowrite32be).

Signed-off-by: Kevin Cernekee <cernekee@gmail.com>
Signed-off-by: Greg Kroah-Hartman <gregkh@linuxfoundation.org>
diff --git a/include/linux/serial_core.h b/include/linux/serial_core.h
index 3231a43..057038c 100644
--- a/include/linux/serial_core.h
+++ b/include/linux/serial_core.h
@@ -142,12 +142,13 @@
 	unsigned char		iotype;			/* io access style */
 	unsigned char		unused1;
 
-#define UPIO_PORT		(0)
-#define UPIO_HUB6		(1)
-#define UPIO_MEM		(2)
-#define UPIO_MEM32		(3)
-#define UPIO_AU			(4)			/* Au1x00 and RT288x type IO */
-#define UPIO_TSI		(5)			/* Tsi108/109 type IO */
+#define UPIO_PORT		(0)			/* 8b I/O port access */
+#define UPIO_HUB6		(1)			/* Hub6 ISA card */
+#define UPIO_MEM		(2)			/* 8b MMIO access */
+#define UPIO_MEM32		(3)			/* 32b little endian */
+#define UPIO_MEM32BE		(4)			/* 32b big endian */
+#define UPIO_AU			(5)			/* Au1x00 and RT288x type IO */
+#define UPIO_TSI		(6)			/* Tsi108/109 type IO */
 
 	unsigned int		read_status_mask;	/* driver specific */
 	unsigned int		ignore_status_mask;	/* driver specific */