USB serial: make USB device id constant

The id_table field of the struct usb_device_id is constant in <linux/usb.h>
so it is worth to make the initialization data also constant.

The semantic match that finds this kind of pattern is as follows:
(http://coccinelle.lip6.fr/)

// <smpl>
@r@
disable decl_init,const_decl_init;
identifier I1, I2, x;
@@
	struct I1 {
	  ...
	  const struct I2 *x;
	  ...
	};
@s@
identifier r.I1, y;
identifier r.x, E;
@@
	struct I1 y = {
	  .x = E,
	};
@c@
identifier r.I2;
identifier s.E;
@@
	const struct I2 E[] = ... ;
@depends on !c@
identifier r.I2;
identifier s.E;
@@
+	const
	struct I2 E[] = ...;
// </smpl>

Signed-off-by: Németh Márton <nm127@freemail.hu>
Cc: Julia Lawall <julia@diku.dk>
Cc: cocci@diku.dk
Signed-off-by: Greg Kroah-Hartman <gregkh@suse.de>

diff --git a/drivers/usb/serial/io_tables.h b/drivers/usb/serial/io_tables.h
index 9241d31..feb56a4 100644
--- a/drivers/usb/serial/io_tables.h
+++ b/drivers/usb/serial/io_tables.h
@@ -14,7 +14,7 @@
 #ifndef IO_TABLES_H
 #define IO_TABLES_H
 
-static struct usb_device_id edgeport_2port_id_table [] = {
+static const struct usb_device_id edgeport_2port_id_table[] = {
 	{ USB_DEVICE(USB_VENDOR_ID_ION, ION_DEVICE_ID_EDGEPORT_2) },
 	{ USB_DEVICE(USB_VENDOR_ID_ION, ION_DEVICE_ID_EDGEPORT_2I) },
 	{ USB_DEVICE(USB_VENDOR_ID_ION, ION_DEVICE_ID_EDGEPORT_421) },
@@ -23,7 +23,7 @@
 	{ }
 };
 
-static struct usb_device_id edgeport_4port_id_table [] = {
+static const struct usb_device_id edgeport_4port_id_table[] = {
 	{ USB_DEVICE(USB_VENDOR_ID_ION, ION_DEVICE_ID_EDGEPORT_4) },
 	{ USB_DEVICE(USB_VENDOR_ID_ION, ION_DEVICE_ID_RAPIDPORT_4) },
 	{ USB_DEVICE(USB_VENDOR_ID_ION, ION_DEVICE_ID_EDGEPORT_4T) },
@@ -37,7 +37,7 @@
 	{ }
 };
 
-static struct usb_device_id edgeport_8port_id_table [] = {
+static const struct usb_device_id edgeport_8port_id_table[] = {
 	{ USB_DEVICE(USB_VENDOR_ID_ION, ION_DEVICE_ID_EDGEPORT_8) },
 	{ USB_DEVICE(USB_VENDOR_ID_ION, ION_DEVICE_ID_EDGEPORT_16_DUAL_CPU) },
 	{ USB_DEVICE(USB_VENDOR_ID_ION, ION_DEVICE_ID_EDGEPORT_8I) },
@@ -47,7 +47,7 @@
 	{ }
 };
 
-static struct usb_device_id Epic_port_id_table [] = {
+static const struct usb_device_id Epic_port_id_table[] = {
 	{ USB_DEVICE(USB_VENDOR_ID_NCR, NCR_DEVICE_ID_EPIC_0202) },
 	{ USB_DEVICE(USB_VENDOR_ID_NCR, NCR_DEVICE_ID_EPIC_0203) },
 	{ USB_DEVICE(USB_VENDOR_ID_NCR, NCR_DEVICE_ID_EPIC_0310) },
@@ -60,7 +60,7 @@
 };
 
 /* Devices that this driver supports */
-static struct usb_device_id id_table_combined [] = {
+static const struct usb_device_id id_table_combined[] = {
 	{ USB_DEVICE(USB_VENDOR_ID_ION,	ION_DEVICE_ID_EDGEPORT_4) },
 	{ USB_DEVICE(USB_VENDOR_ID_ION,	ION_DEVICE_ID_RAPIDPORT_4) },
 	{ USB_DEVICE(USB_VENDOR_ID_ION,	ION_DEVICE_ID_EDGEPORT_4T) },